Author name code: turck-chieze ADS astronomy entries on 2022-09-14 author:"Turck-Chieze, Sylvaine" ------------------------------------------------------------------------ Title: Stellar Atomic Opacities Authors: Turck-Chiéze, S. Bibcode: 2018ASPC..515....3T Altcode: Atomic opacities are fundamental ingredients of stellar evolution: they largely determine the energy transfer inside the stellar interiors and play crucial roles in the stellar ages and in any thermodynamic indicator. They are determined by complex atomic calculations performed for a large range of temperatures and densities and numerous ionic species. Therefore, their knowledge was for a long time purely theoretical, and the available tables were the result of different approaches often used as black boxes. Differences were observed among them but their origin was not so clear; their resolution has been stimulated by the development of stellar seismology that scrutinizes the stellar interiors, and by the hope of astrophysicists to validate the physics contained in the stellar evolution codes. In the 1990s the high quality of the measured solar neutrino fluxes and of the solar acoustic modes encouraged an update of these calculations. At the same time the first dedicated opacity measurements have also been performed. During the last decade the asteroseismic space probes (COROT, KEPLER) have encouraged new comparisons between the theoretical teams (mainly in France and the USA) and the generation of new tables. Opacity measurements at the Sandia Laboratory Z facility and promising ones on high-energy laser facilities (OMEGA, NIF, LMJ) present new challenges for accurate opacities. This review shows an astrophysicist's point of view with interesting comparisons and suggestions for new perspectives. Title: Progress on a Double Ablation Front Scheme for Iron Spectral Opacity Measurements in Solar Conditions Authors: Colaïtis, A.; Ducret, J. -E.; Turck-Chièze, S.; Le Pennec, M.; Jacquet, L.; Blancard, C. Bibcode: 2018ASPC..515..104C Altcode: We propose a new method to verify the radiation transport properties of the plasma at the base of the solar convection zone. The method is designed for high-power lasers, and exploits the temporal and spatial stability of hydrodynamic parameters in counter-propagating double ablation front (DAF) structures. One-dimensional radiative hydrodynamic simulations of a symmetric DAF structure are studied in the presence of tracer layers. In this framework an iron sample with electron number density ne∼ 2×1023 cm-3 can be taken to an electron temperature of Te∼ 200 eV. These conditions are obtained for 500 ps with small longitudinal gradients and with matter very near to local thermodynamical equilibrium. These results led to an experimental design compatible with the OMEGA laser of Boehly et al. (1997). We discuss the findings of a preliminary campaign conducted in 2017. Title: Current State of Astrophysical Opacities: A White Paper Authors: Lynas-Gray, A. E.; Basu, S.; Bautista, M. A.; Colgan, J.; Mendoza, C.; Tennyson, J.; Trampedach, R.; Turck-Chièze, S. Bibcode: 2018ASPC..515..301L Altcode: 2018arXiv180406804L Availability of reliable atomic and molecular opacity tables is essential in a wide variety of astronomical modeling: the solar and stellar interiors, stellar and planetary atmospheres, stellar evolution, pulsating stars, and protoplanetary disks, to name a few. With the advancement of powerful research techniques—such as helioseismology and asteroseismology, solar neutrino-flux measurements, exoplanet survey satellites, three-dimensional hydrodynamic atmospheric simulations (including non-LTE and granulation effects), high-performance computing of atomic and molecular data, and innovative plasma experiments—the accuracy and completeness of opacity tables is being taken to an unprecedented level. The goal of the second Workshop on Astrophysical Opacities was to gather opacity data producers and consumers from both the atomic and molecular sectors to contribute to solving outstanding problems and to develop more effective and integrated interfaces. In this review we attempt to summarize the discussion at the workshop and propose future directions for opacity research. Title: Workshop on Astrophysical Opacities Authors: Mendoza, C.; Turck-Chiéze, S.; Colgan, J. Bibcode: 2018ASPC..515....0M Altcode: No abstract at ADS Title: Seismic inversion of the solar entropy. A case for improving the standard solar model Authors: Buldgen, G.; Salmon, S. J. A. J.; Noels, A.; Scuflaire, R.; Reese, D. R.; Dupret, M. -A.; Colgan, J.; Fontes, C. J.; Eggenberger, P.; Hakel, P.; Kilcrease, D. P.; Turck-Chièze, S. Bibcode: 2017A&A...607A..58B Altcode: 2017arXiv170705138B Context. The Sun is the most constrained and well-studied of all stars. As a consequence, the physical ingredients entering solar models are used as a reference to study all other stars observed in the Universe. However, our understanding of the solar structure is still imperfect, as illustrated by the current debate on the heavy element abundances in the Sun.
Aims: We provide additional information on the solar structure by carrying out structural inversions of a new physical quantity, a proxy of the entropy of the solar plasma whose properties are very sensitive to the temperature gradient below the convective zone.
Methods: We use new structural kernels to carry out direct inversions of an entropy proxy of the solar plasma and compare the solar structure to various standard solar models built using various opacity tables and chemical abundances. We also link our results to classical tests commonly found in the literature.
Results: Our analysis allows us to probe more efficiently the uncertain regions of the solar models, just below the convective zone, paving the way for new in-depth analyses of the Sun taking into account additional physical uncertainties of solar models beyond the specific question of chemical abundances. Title: Detection of g modes in the asymptotic frequency range: evidence for a rapidly rotating core Authors: Ulrich, Roger K.; Fossat, Eric; Boumier, Patrick; Corbard, Thierry; Provost, Janine; Salabert, David; Schmider, François-Xavier; Gabriel, Alan; Grec, Gerard; Renaud, Catherine; Robillot, Jean-Maurice; Roca Cortés, Teodoro; Turck-Chièze, Sylvaine Bibcode: 2017SPD....4810906U Altcode: We present the identification of very low frequency g modes, in the asymptotic regime, and two important parameters: the core rotation rate and the asymptotic equidistant period spacing of these g modes. The GOLF instrument on the SOHO space observatory has provided two decades of full disk helioseismic data. The search for g modes in GOLF measurements has been extremely difficult, due to solar and instrumental noise. In the present study, the p modes of the GOLF signal are analyzed differently, searching for possible collective frequency modulations produced by periodic changes in the deep solar structure. Such modulations provide access to only very low frequency g modes, thus allowing statistical methods to take advantage of their asymptotic properties. For oscillatory periods in the range between 9 and nearly 48 hours, almost 100 g modes of spherical harmonic degree 1 and more than 100 g modes of degree 2 are predicted. They are not observed individually, but when combined, they unambiguously provide their asymptotic period equidistance and rotational splittings, in excellent agreement with the requirements of the asymptotic approximations. P0, the g-mode period equidistance parameter, is measured to be 34 min 01 s, with a 1 s uncertainty. The previously unknown g-mode splittings have now been measured from a non synodic reference with a very high accuracy, and they imply a mean weighted rotation of 1277 ± 10 nHz (9-day period) of their kernels, resulting in a rapid rotation frequency of 1644 ± 23 nHz (period of one week) of the solar core itself, which is a factor 3:8 ± 0:1 faster than the rotation of the radiative envelope.Acknowledgements. Ulrich is first author on this abstract due to AAS rules, Fossat is the actual first author. SOHO is a project of international collaboration between ESA and NASA. We would like to acknowledge the support received continuously during more than 3 decades from CNES. DS acknowledges the financial support from the CNES GOLF grant and the Observatoire de la Côte d’Azur for support during his stays. RKU acknowledges support from NASA for his participation in this project and thanks John Bahcall for enthusiastic encouragement for the g-mode search. Title: Asymptotic g modes: Evidence for a rapid rotation of the solar core Authors: Fossat, E.; Boumier, P.; Corbard, T.; Provost, J.; Salabert, D.; Schmider, F. X.; Gabriel, A. H.; Grec, G.; Renaud, C.; Robillot, J. M.; Roca-Cortés, T.; Turck-Chièze, S.; Ulrich, R. K.; Lazrek, M. Bibcode: 2017A&A...604A..40F Altcode: 2017arXiv170800259F Context. Over the past 40 years, helioseismology has been enormously successful in the study of the solar interior. A shortcoming has been the lack of a convincing detection of the solar g modes, which are oscillations driven by gravity and are hidden in the deepest part of the solar body - its hydrogen-burning core. The detection of g modes is expected to dramatically improve our ability to model this core, the rotational characteristics of which have, until now, remained unknown.
Aims: We present the identification of very low frequency g modes in the asymptotic regime and two important parameters that have long been waited for: the core rotation rate, and the asymptotic equidistant period spacing of these g modes.
Methods: The GOLF instrument on board the SOHO space observatory has provided two decades of full-disk helioseismic data. The search for g modes in GOLF measurements has been extremely difficult because of solar and instrumental noise. In the present study, the p modes of the GOLF signal are analyzed differently: we search for possible collective frequency modulations that are produced by periodic changes in the deep solar structure. Such modulations provide access to only very low frequency g modes, thus allowing statistical methods to take advantage of their asymptotic properties.
Results: For oscillatory periods in the range between 9 and nearly 48 h, almost 100 g modes of spherical harmonic degree 1 and more than 100 g modes of degree 2 are predicted. They are not observed individually, but when combined, they unambiguously provide their asymptotic period equidistance and rotational splittings, in excellent agreement with the requirements of the asymptotic approximations. When the period equidistance has been measured, all of the individual frequencies of each mode can be determined. Previously, p-mode helioseismology allowed the g-mode period equidistance parameter P0 to be bracketed inside a narrow range, between approximately 34 and 35 min. Here, P0 is measured to be 34 min 01 s, with a 1 s uncertainty. The previously unknown g-mode splittings have now been measured from a non-synodic reference with very high accuracy, and they imply a mean weighted rotation of 1277 ± 10 nHz (9-day period) of their kernels, resulting in a rapid rotation frequency of 1644 ± 23 nHz (period of one week) of the solar core itself, which is a factor 3.8 ± 0.1 faster than the rotation of the radiative envelope.
Conclusions: The g modes are known to be the keys to a better understanding of the structure and dynamics of the solar core. Their detection with these precise parameters will certainly stimulate a new era of research in this field. Title: Experiment to measure oxygen opacity at high density and temperature Authors: Keiter, Paul; Mussack, Katie; Orban, Chris; Colgan, James; Ducret, Jean-Eric; Fontes, Christopher J.; Guzik, Joyce Ann; Heeter, Robert F.; Kilcrease, Dave; Le Pennec, Maelle; Mancini, Roberto; Perry, Ted; Turck-Chièze, Sylvaine; Trantham, Matt Bibcode: 2017AAS...23021317K Altcode: In recent years, there has been a debate over the abundances of heavy elements (Z >2) in the solar interior. Recent solar atmosphere models [Asplund 2009] find a significantly lower abundance for C, N, and O compared to models used roughly a decade ago. This discrepancy has led to an investigation of opacities through laboratory experiments and improved opacity models for many of the larger contributors to the sun’s opacity, including iron and oxygen. Recent opacity measurements of iron disagree with opacity model predictions [Bailey et al, 2015]. Although these results are still controversial, repeated scrutiny of the experiment and data has not produced a conclusive reason for the discrepancy. New models have been implemented in the ATOMIC opacity code for C, O and Fe to address the solar abundance issue [Colgan, 2013]. Armstrong et al [2014] have also implemented changes in the ATOMIC code for low-Z elements. However, no data currently exists to test the low-Z material models in the regime relevant to the solar convection zone. We present an experimental design using the opacity platform developed at the National Ignition Facility to study the oxygen opacity at densities and temperatures near the solar convection zone conditions.This work is funded by the U.S. DOE, through the NNSA-DS and SC-OFES Joint Program in HEDPLP, grant No. DE-NA0001840, and the NLUF Program, grant No. DE-NA0000850, and through LLE, University of Rochester by the NNSA/OICF under Agreement No. DE-FC52-08NA28302. Title: Future Mission Concepts for Helioseismology Authors: Sekii, Takashi; Appourchaux, Thierry; Fleck, Bernhard; Turck-Chièze, Sylvaine Bibcode: 2017hdsi.book..291S Altcode: No abstract at ADS Title: Understanding the Internal Chemical Composition and Physical Processes of the Solar Interior Authors: Basu, Sarbani; Grevesse, Nicolas; Mathis, Stephane; Turck-Chièze, Sylvaine Bibcode: 2017hdsi.book...55B Altcode: No abstract at ADS Title: Main results of the PICARD mission Authors: Meftah, M.; Corbard, T.; Hauchecorne, A.; Irbah, A.; Boumier, P.; Chevalier, A.; Schmutz, W.; Ikhlef, R.; Morand, F.; Renaud, C.; Hochedez, J. -F.; Cessateur, G.; Turck-Chièze, S.; Salabert, D.; Rouzé, M.; van Ruymbeke, M.; Zhu, P.; Kholikov, S.; Koller, S.; Conscience, C.; Dewitte, S.; Damé, L.; Djafer, D. Bibcode: 2016SPIE.9904E..0ZM Altcode: PICARD is a mission devoted to solar variability observations through imagery and radiometric measurements. The main goal is to provide data for scientific investigation first in the area of solar physics, and second in the assessment of the influence of the solar variability on the Earth climate variability. PICARD contains a double program with in-space and on-ground measurements. The PICARD spacecraft was launched on June 15, 2010, commissioned in-flight in October of the same year and was retired in April 2014. The PICARD ground-based observatory is operational since May 2011. We shall give a short overview of the PICARD instrumentation. New estimates of the absolute values of the total solar irradiance, of the solar spectral irradiance at typical wavelengths, and of the solar oblateness will be given. We will also report about helioseismic studies. Finally, we will present our current results about solar radius variations after six years of solar observation. Title: On the Current Solar Magnetic Activity using Its Behavior During the Holocene Authors: Inceoglu, Fadil; Simoniello, Rosaria; Faurschou Knudsen, Mads; Karoff, Christoffer; Olsen, Jesper; Turck-Chieze, Sylvaine Bibcode: 2016cosp...41E.862I Altcode: Solar modulation potential (SMP) reconstructions based on cosmogenic nuclide records reflect changes in the open solar magnetic field and can therefore help us obtain information on the behavior of the open solar magnetic field over the Holocene period. Using the Greenland Ice Core Project (GRIP) ^{10}Be and IntCal13 ^{14}C records for the overlapping time period spanning between ∼1650 AD to 6600 BC, we first reconstructed the solar modulation potentials and subsequently investigate the statistics of peaks and dips simultaneously occurring in the two SMP reconstructions. Based on the distribution of these events, we propose a method to identify grand minima and maxima periods. We then aim at comparing the Sun's large-scale magnetic field behavior over the last three solar cycles with variations in the SMP reconstruction through the Holocene epoch. To achieve these objectives, we use the IntCal13 ^{14}C data to investigate distinct patterns in the occurrences of grand minima and maxima during the Holocene period. We then check whether these patterns might mimic the recent solar magnetic activity by investigating the evolution of the energy in the Sun's large-scale dipolar magnetic field using the Wilcox Solar Observatory data. The cosmogenic radionuclide data analysis shows that ∼71 % of grand maxima during the period from 6600 BC to 1650 AD were followed by a grand minimum. The characteristics of the occurrences of grand maxima and minima are consistent with the scenario in which the dynamical non-linearity induced by the Lorentz force leads the Sun to act as a relaxation oscillator. This finding implies that the probability for these events to occur is non-uniformly distributed in time, as there is a memory in their driving mechanism, which can be identified via the back-reaction of the Lorentz force. Title: Detailed Opacity Comparison for an Improved Stellar Modeling of the Envelopes of Massive Stars Authors: Turck-Chièze, S.; Le Pennec, M.; Ducret, J. E.; Colgan, J.; Kilcrease, D. P.; Fontes, C. J.; Magee, N.; Gilleron, F.; Pain, J. C. Bibcode: 2016ApJ...823...78T Altcode: Seismic observations have led to doubts or ambiguities concerning the opacity calculations used in stellar physics. Here, we concentrate on the iron-group opacity peak, due to iron, nickel, and chromium, located around T = 200,000 K for densities from {10}-8 {to} {10}-4 {{g}} {{cm}}-3, which creates some convective layers in stellar radiative envelopes for masses between 3 and 18 {M}⊙ . These conditions were extensively studied in the 1980s. More recently, inconsistencies between OP and OPAL opacity calculations have complicated the interpretation of seismic observations as the iron-group opacity peak excites acoustic and gravity modes in SPB, β Cephei, and sdB stars. We investigate the reliability of the theoretical opacity calculations using the modern opacity codes ATOMIC and SCO-RCG. We show their temperature and density dependence for conditions that are achievable in the laboratory and equivalent to astrophysical conditions. We also compare new theoretical opacity spectra with OP spectra and quantify how different approximations impact the Rosseland mean calculations.This detailed study estimates new ATOMIC and SCO-RCG Rosseland mean values for astrophysical conditions which we compare to OP values. Some puzzling questions are still under investigation for iron, but we find a strong increase in the Rosseland mean nickel opacity of a factor between 2 and 6 compared to OP. This appears to be due to the use of extrapolated atomic data for the Ni opacity within the OP calculations. A study on chromium is also shown. Title: The Standard Solar Model and beyond Authors: Turck-Chièze, S. Bibcode: 2016JPhCS.665a2078T Altcode: The Standard Solar Model (SSM) is an important reference in Astrophysics as the Sun stays today the most observed star. This model is used to predict the internal observables like neutrino fluxes and oscillation frequencies and consequently to validate its assumptions for its generalization to other stars. The model outputs result from the resolution of the classical stellar equations and the knowledge of fundamental physics like nuclear reaction rates, screening, photon interaction, plasma physics. The plasma conditions remained unmeasurable in laboratory for long due to the high temperature and high density conditions of the solar interior. Today, neutrino detections and helioseismology aboard SoHO have largely revealed the solar interior, in particular the nuclear solar core so one can estimate the reliability of SSM and also its coherence with the different indicators and between them. This has been possible thanks to a Seismic Solar Model (SeSM) which takes into account in addition the observed sound speed profile. Seismology quantifies also some internal dynamical processes that need to be properly introduced in the description of stars. This review describes the different steps of building of the SSM, its predictions and the comparisons with observations. It discusses the accuracy of such model compared to the accuracy of the SeSM. The noticed differences and observational constraints put some limits on other possible processes like dark matter, magnetic field or waves and determine the directions of progress for the near future that will come from precise emitted neutrino fluxes. High density laser facilities promise also unprecedented checks of energy transfer by photons and nuclear reaction rates. Title: On the Current Solar Magnetic Activity in the Light of Its Behaviour During the Holocene Authors: Inceoglu, F.; Simoniello, R.; Knudsen, M. F.; Karoff, C.; Olsen, J.; Turck-Chièze, S. Bibcode: 2016SoPh..291..303I Altcode: 2015arXiv150906182I; 2015SoPh..tmp..159I Solar modulation potential (SMP) reconstructions based on cosmogenic nuclide records reflect changes in the open solar magnetic field and can therefore help us obtain information on the behaviour of the open solar magnetic field over the Holocene period. We aim at comparing the Sun's large-scale magnetic field behaviour over the last three solar cycles with variations in the SMP reconstruction through the Holocene epoch. To achieve these objectives, we use the IntCal13 14C data to investigate distinct patterns in the occurrences of grand minima and maxima during the Holocene period. We then check whether these patterns might mimic the recent solar magnetic activity by investigating the evolution of the energy in the Sun's large-scale dipolar magnetic field using the Wilcox Solar Observatory data. The cosmogenic radionuclide data analysis shows that ≈71 % of grand maxima during the period from 6600 BC to 1650 AD were followed by a grand minimum. The characteristics of the occurrences of grand maxima and minima are consistent with the scenario in which the dynamical non-linearity induced by the Lorentz force leads the Sun to act as a relaxation oscillator. This finding implies that the probability for these events to occur is non-uniformly distributed in time, as there is a memory in their driving mechanism, which can be identified via the back-reaction of the Lorentz force. Title: Understanding the Internal Chemical Composition and Physical Processes of the Solar Interior Authors: Basu, Sarbani; Grevesse, Nicolas; Mathis, Stephane; Turck-Chièze, Sylvaine Bibcode: 2015SSRv..196...49B Altcode: 2014SSRv..tmp....3B The Sun, the closest and most well studied of stars, is generally used as a standard that other stars are compared to. Models of the Sun are constantly tested with helioseismic data. These data allow us to probe the internal structure and dynamics of the Sun. Among the main sources of the data is the SOHO spacecraft that has been continuously observing the Sun for more than a solar cycle. Current solar models, although good, do not include all the physical processes that are present in the Sun. In this chapter we focus on specific inputs to solar models and discuss generally neglected dynamical physical processes whose inclusion could result in models that are much better representatives of the Sun. Title: New opacity measurement principle for LMJ-PETAL laser facility Authors: Le Pennec, M.; Ribeyre, X.; Ducret, J. -E.; Turck-Chièze, S. Bibcode: 2015HEDP...17..162L Altcode: 2015arXiv150903563L Stellar seismology reveals some interior properties of thousands of solar-type stars but the solar seismic sound speed stays puzzling since a decade as it disagrees with the Standard Solar Model (SSM) prediction. One of the explanations of this disagreement may be found in the treatment of the transport of radiation from the solar core to the surface. As the same framework is used for other stars, it is important to check precisely the reliability of the interacting cross sections of photons with each species in order to ensure the energy transport for temperature T > 2-106 K and density ρ > 0.2 g/cm3. In this paper, we propose a new technique to reach the domain of temperature and density found in the solar radiative interior. This technique called the Double Ablation Front (DAF) is based on a high conversion of the laser energy into X-rays thanks to moderated Z material irradiated by laser intensity between 1.5 × 1015 W/cm2 and 4 × 1015 W/cm2. This high conversion creates, in addition to the electronic front a second ablation front in the moderated Z material. Between the two fronts there is a plateau of density and temperature that we exploit to heat a sample of iron or of oxide. The first simulations realized with the hydrodynamic code CHIC show that this technique allows to reach conditions equivalent to half the radiative zone of the Sun with high stability both in time and space. We examine the possibility to measure both iron and oxygen absorption spectra. Title: Asteroseismic hare & hound exercises: the case of β Cephei stars Authors: Salmon, S. J. A. J.; Montalbán, J.; Miglio, A.; Noels, A.; Dupret, M. -A.; Eggenberger, P.; Turck-Chièze, S. Bibcode: 2015sf2a.conf..423S Altcode: The β Cephei pulsating stars present a unique opportunity to test and probe our knowledge of the interior of massive stars. The information that we can get depends on the quality and number of observational constraints, both seismic and classical ones. The asteroseismology of β Cephei stars proceeds by a forward approach, which can result in multiple solutions, without clear indication on the level of confidence. We seek a method to derive confidence intervals on stellar parameters and investigate how these latter behave depending on the seismic data accessible to the observer. We realise forward modelling with the help of a grid of pre-computed models. We also use Monte-Carlo simulations to build confidence intervals on the inferred stellar parameters. We apply and test this method in a series of hare and hound exercises on a subset of theoretical models simulating observed stars. Results show that a set of 5 frequencies (with knowledge of their associated angular degree) yields precise seismic constraints. Significant errors on the determination of the extent of the central mixed region may result when the theoretical models do not present the same chemical mixture as the observed star. Title: Future Mission Concepts for Helioseismology Authors: Sekii, Takashi; Appourchaux, Thierry; Fleck, Bernhard; Turck-Chièze, Sylvaine Bibcode: 2015SSRv..196..285S Altcode: 2015SSRv..tmp...15S Future space-mission concepts currently discussed in the helioseismology community are reviewed. One popular idea is to observe the Sun from high latitudes, to explore the polar regions as well as to probe the deep interior using stereoscopic techniques, by combining observations from high latitudes with observations from within the ecliptic plane. Another idea is to stay within the ecliptic plane but still aim for stereoscopic helioseismology for deep layers. A new instrument and a novel mission concept for studying the solar core regions are also discussed. Title: First New Solar Models with OPAS Opacity Tables Authors: Le Pennec, M.; Turck-Chièze, S.; Salmon, S.; Blancard, C.; Cossé, P.; Faussurier, G.; Mondet, G. Bibcode: 2015ApJ...813L..42L Altcode: 2015arXiv151005600L Stellar seismology appears more and more as a powerful tool for a better determination of the fundamental properties of solar-type stars. However, the particular case of the Sun is still challenging. For about a decade now, the helioseismic sound-speed determination has continued to disagree with the standard solar model (SSM) prediction, questioning the reliability of this model. One of the sources of uncertainty could be in the treatment of the transport of radiation from the solar core to the surface. In this Letter, we use the new OPAS opacity tables, recently available for solar modeling, to address this issue. We discuss first the peculiarities of these tables, then we quantify their impact on the solar sound-speed and density profiles using the reduced OPAS tables taken on the grids of the OPAL ones. We use the two evolution codes, Modules for Experiments in Stellar Astrophysics and Code Liégeois d’Evolution Stellaire, that led to similar conclusions in the solar radiative zone. In comparison to commonly used OPAL opacity tables, the new solar models are computed for the most recent photospheric composition with OPAS tables and present improvements to the location of the base of the convective zone and to the description of the solar radiative zone in comparison to the helioseismic observations, even if the differences in the Rosseland mean opacity do not exceed 6%. We finally carry out a comparison to a solar model computed with the OP opacity tables. Title: Testing stellar opacities with laser facilities Authors: Le Pennec, Maëlle; TURCK-CHIEZE, Sylvaine; RIBEYRE, Xavier; DUCRET, Jean-Eric; SALMON, Sébastien; BLANCARD, Christophe; COSSE, Philippe; MONDET, Guillaume; FAUSSURIER, Gérald; CONSORTIUM, OPAC Bibcode: 2015IAUGA..2255164L Altcode: Helio and asteroseismology (SoHo, KEPLER...) have produced observed acoustic oscillations of thousands of stars which characteristics are deeply linked to the transport of radiation inside the stars. However, the comparisons of seismic data with model predictions have led to significant discrepancies, which could be due to a bad knowledge of production and transport of energy.β-Cephei are pulsating stars, progenitor of supernovae and thus deeply linked to our understanding of stellar medium enrichment. Their study has shown some difficulty to predict the observed oscillation modes, which are directly linked to an opacity bump of the elements of the iron group (Cr, Fe, Ni) at log T=5.25 (κ-mechanism). We will show that several parameters of the stars (mass, age, metallicity) have a great influence on the amplitude of the bump, which impact their structure. We will then present the final results of an experiment conducted at LULI 2000 in 2011 on Cr, Fe and Ni compared to several opacity codes. We will show how to improve the opacity in the range of temperature around log T= 5.3.The Sun is a privilege place to test and validate physics. Since the recent update of the solar composition, there is a well established large discrepancy (Turck-Chièze et al. 2001) between solar models and seismic data, visible on the solar sound speed profile comparison.An explanation could be that the calculations of energy transport are not correctly taken into account.Unfortunately, there are very few experiments to validate these calculations (Bailey et al. 2014). That's why we are proposing an opacity experiment on a high-energy laser like LMJ, in the conditions of the radiative zone. We are exploiting in that purpose an approach called the Double Ablation Front to reach these high temperatures and densities at LTE and validate or not plasma effects and line widths. We will show the principle of this technique and the results of our simulations on several elements.In the mean time, we are also exploiting new opacity calculations thanks to the OPAS code (Blancard et al. 2012) at the conditions of the solar radiative zone. We will show the impact of these calculations on the solar model. Title: Validating solar and solar-like star opacities Authors: Le Pennec, Maëlle; TURCK-CHIEZE, Sylvaine; RIBEYRE, Xavier; DUCRET, Jean-Eric; BLANCARD, Christophe; COSSE, Philippe; MONDET, Guillaume; FAUSSURIER, Gérald Bibcode: 2015IAUGA..2255142L Altcode: The Sun is, as being our closest star, a privilege place to test and validate physics. However, the solar physics is not yet completely understood. Indeed, since the recent update of the solar composition, there are differences between solar models and seismic data, visible on the solar sound speed profile comparison. This well established large discrepancy (Turck-Chièze et al. 2001, 2004, 2011, Christensen-Dalsgaard et al. 2009, Basu et al. 2015) could be linked to radiative transfer issue.Two directions of investigation are proposed. One possibility to explain this gap could be that the Sun produces slightly more energy that it liberates on its surface (around 5%). This energy could be transformed into macroscopic motions in the radiative zone, which are not taken into account in the solar standard model. Another explanation could be that the calculations of energy transport are not correctly taken into account either on the calculation of the Rosseland mean values or in the treatment of the radiative acceleration. This could have an impact on the determination of the internal solar abundances.Unfortunately, there are very few experiments to validate these calculations (Bailey et al. 2014). That's why we are proposing an opacity experiment on a high-energy laser like LMJ, in the conditions of the radiative zone (T=[2 - 15.106 K] and ρ=[0.2 - 150 g/cm3]). The aim is to measure the opacity of the most important contributors to the global opacity in this solar area : iron, oxygen and silicon. We are exploiting in that purpose a technical approach called the Double Ablation Front. During the laser-plasma interaction, the plasma radiative effects allow to reach these high temperatures and densities at LTE and validate or not plasma effects and line widths. We will show the principle of this technique and the results of our simulations on several elements.In the mean time, we are also exploiting new opacity calculations thanks to the OPAS code (Blancard et al. 2012) at the conditions of the solar radiative zone. We will show the impact of these calculations on the solar model. Title: Opacities in the massive stellar envelopes Authors: Le Pennec, Maëlle; TURCK-CHIEZE, Sylvaine; SALMON, Sébastien; CONSORTIUM, OPAC Bibcode: 2015IAUGA..2255248L Altcode: Helio and asteroseismology (SoHo, CoRoT, KEPLER...) have produced observed acoustic oscillations of thousands of stars. The characteristics of these oscillations are deeply linked to the transport of radiation inside the stars. However, the comparisons of seismic data of Sun and stars with model predictions have led to significant discrepancies, which could be due to a bad knowledge of production and transport of energy.We will focus here on the case of β-Cephei.β-Cephei are pulsating stars, progenitor of supernovae and thus deeply linked to our understanding of stellar medium enrichment. Their study has shown some difficulty to predict the observed oscillation modes, which are directly linked to a bump of the opacity of the elements of the iron group (Cr, Fe, Ni) at log T=5.25 through their pulsating mechanism called the κ-mechanism. We will show that the different parameters of the stars (mass, age, metallicity) have a great influence on the amplitude of the bump, and then on the structure of the considered star.The mastery of the κ-mechanism that produces the pulsation of these stars supposes a fine determination of the peak opacity of the iron group in their envelope. We will present the final results of an experiment conducted at LULI 2000 in 2011 on Cr, Fe and Ni and compare them to OP and ATOMIC, SCO-RCG codes. We will show how to improve the opacity in the range of temperature around log T= 5.3. Title: Seismic sensitivity to sub-surface solar activity from 18 yr of GOLF/SoHO observations Authors: Salabert, D.; García, R. A.; Turck-Chièze, S. Bibcode: 2015A&A...578A.137S Altcode: 2015arXiv150207607S Solar activity has significantly changed over the last two Schwabe cycles. After a long and deep minimum at the end of Cycle 23, the weaker activity of Cycle 24 contrasts with the previous cycles. In this work, the response of the solar acoustic oscillations to solar activity is used in order to provide insights into the structural and magnetic changes in the sub-surface layers of the Sun during this on-going unusual period of low activity. We analyze 18 yr of continuous observations of the solar acoustic oscillations collected by the Sun-as-a-star GOLF instrument on board the SoHO spacecraft. From the fitted mode frequencies, the temporal variability of the frequency shifts of the radial, dipolar, and quadrupolar modes are studied for different frequency ranges that are sensitive to different layers in the solar sub-surface interior. The low-frequency modes show nearly unchanged frequency shifts between Cycles 23 and 24, with a time evolving signature of the quasi-biennial oscillation, which is particularly visible for the quadrupole component revealing the presence of a complex magnetic structure. The modes at higher frequencies show frequency shifts that are 30% smaller during Cycle 24, which is in agreement with the decrease observed in the surface activity between Cycles 23 and 24. The analysis of 18 yr of GOLF oscillations indicates that the structural and magnetic changes responsible for the frequency shifts remained comparable between Cycle 23 and Cycle 24 in the deeper sub-surface layers below 1400 km as revealed by the low-frequency modes. The frequency shifts of the higher-frequency modes, sensitive to shallower regions, show that Cycle 24 is magnetically weaker in the upper layers of Sun.

Appendices are available in electronic form at http://www.aanda.orgThe following 68 GOLF frequency tables are available and Table A.1 is also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/578/A137 Title: Grand solar minima and maxima deduced from 10Be and 14C: magnetic dynamo configuration and polarity reversal Authors: Inceoglu, F.; Simoniello, R.; Knudsen, M. F.; Karoff, C.; Olsen, J.; Turck-Chiéze, S.; Jacobsen, B. H. Bibcode: 2015A&A...577A..20I Altcode:
Aims: This study aims to improve our understanding of the occurrence and origin of grand solar maxima and minima.
Methods: We first investigate the statistics of peaks and dips simultaneously occurring in the solar modulation potentials reconstructed using the Greenland Ice Core Project (GRIP) 10Be and IntCal13 14C records for the overlapping time period spanning between ~1650 AD to 6600 BC. Based on the distribution of these events, we propose a method to identify grand minima and maxima periods. By using waiting time distribution analysis, we investigate the nature of grand minima and maxima periods identified based on the criteria as well as the variance and significance of the Hale cycle during these kinds of events throughout the Holocene epoch.
Results: Analysis of grand minima and maxima events occurring simultaneously in the solar modulation potentials, reconstructed based on the 14C and the 10Be records, shows that the majority of events characterized by periods of moderate activity levels tend to last less than 50 years: grand maxima periods do not last longer than 100 years, while grand minima can persist slightly longer. The power and the variance of the 22-year Hale cycle increases during grand maxima and decreases during grand minima, compared to periods characterized by moderate activity levels.
Conclusions: We present the first reconstruction of the occurrence of grand solar maxima and minima during the Holocene based on simultaneous changes in records of past solar variability derived from tree-ring 14C and ice-core 10Be, respectively. This robust determination of the occurrence of grand solar minima and maxima periods will enable systematic investigations of the influence of grand solar minima and maxima episodes on Earth's climate. Title: On the Determination and Constancy of the Solar Oblateness Authors: Meftah, M.; Irbah, A.; Hauchecorne, A.; Corbard, T.; Turck-Chièze, S.; Hochedez, J. -F.; Boumier, P.; Chevalier, A.; Dewitte, S.; Mekaoui, S.; Salabert, D. Bibcode: 2015SoPh..290..673M Altcode: 2015SoPh..tmp...22M The equator-to-pole radius difference (Δr=Req−Rpol) is a fundamental property of our star, and understanding it will enrich future solar and stellar dynamical models. The solar oblateness (Δ⊙) corresponds to the excess ratio of the equatorial solar radius (Req) to the polar radius (Rpol), which is of great interest for those working in relativity and different areas of solar physics. Δr is known to be a rather small quantity, where a positive value of about 8 milli-arcseconds (mas) is suggested by previous measurements and predictions. The Picard space mission aimed to measure Δr with a precision better than 0.5 mas. The Solar Diameter Imager and Surface Mapper (SODISM) onboard Picard was a Ritchey-Chrétien telescope that took images of the Sun at several wavelengths. The SODISM measurements of the solar shape were obtained during special roll maneuvers of the spacecraft by 30° steps. They have produced precise determinations of the solar oblateness at 782.2 nm. After correcting measurements for optical distortion and for instrument temperature trend, we found a solar equator-to-pole radius difference at 782.2 nm of 7.9±0.3 mas (5.7±0.2 km) at one σ. This measurement has been repeated several times during the first year of the space-borne observations, and we have not observed any correlation between oblateness and total solar irradiance variations. Title: VizieR Online Data Catalog: Solar acoustic modes in period 1996-2014 (Salabert+, 2015) Authors: Salabert, D.; Garcia, R. A.; Turck-Chieze, S. Bibcode: 2015yCat..35780137S Altcode: The central frequencies of the l = 0, 1, 2, and 3 acoustic modes of oscillations of the Sun between 1500{micro}Hz and 4000{micro}Hz and their associated formal 1σ uncertainties extracted from 365-day subseries of 18 years of the space-based, Sun-as-a-star GOLF/SoHO observations between 1996 April 11, and 2014 March 5 are presented. As a four-time overlap of 91.25 days was used, a total of 69 frequency tables are provided. We note that one of every four frequency tables contains frequencies extracted from independent subseries. Quality criteria were defined based on the fitted mode parameters and their associated uncertainties in order to remove outliers. An info file containing the associated starting date and duty cycle of each 365-day subseries is also provided. The corresponding mean 10.7cm radio flux is also given in the info file.

(2 data files). Title: Stellar opacity validations Authors: Le Pennec, M.; Turck-Chièze, S.; Ribeyre, X.; Ducret, J. E. Bibcode: 2014sf2a.conf..487L Altcode: This paper focuses on the radiative transfer in stars where opacities seem to raise problems : β-Cephei and solar-type stars. We first concentrate on the iron bump (log T = 5.25), responsible for β-Cephei pulsations through the κ-mechanism. To discriminate between the different opacity calculations used to predict their oscillations, new well-qualified calculations are used and compared to OP calculations. In parallel with this theoretical work, an experiment has been conducted at LULI 2000 in 2011 on iron and nickel. We show that this extended study pushes for the revision of the tables in the conditions corresponding to the iron bump region, at least for nickel. We will then deal with the Sun case for which we are preparing an opacity experiment on a high-energy laser, in some conditions of the radiative zone (T = [2 - 15 ×10^{6} K] and ρ = [0.2 - 150 g/cm^{3}]). To reach these high temperatures and densities at LTE and validate or not plasma effects and line widths, we are exploring an approach called the Double Ablation Front, driven by plasma radiative effects. The 1D simulations performed with the code CHIC show that with this technique, we could reach conditions equivalent to the conditions of half of the solar radiative zone. Title: Detecting Gravity Modes in the Solar 8 B Neutrino Flux Authors: Lopes, Ilídio; Turck-Chièze, Sylvaine Bibcode: 2014ApJ...792L..35L Altcode: 2014arXiv1408.6671L The detection of gravity modes produced in the solar radiative zone has been a challenge in modern astrophysics for more than 30 yr and their amplitude in the core is not yet determined. In this Letter, we develop a new strategy to look for standing gravity modes through solar neutrino fluxes. We note that due to a resonance effect, the gravity modes of low degree and low order have the largest impact on the 8 B neutrino flux. The strongest effect is expected to occur for the dipole mode with radial order 2, corresponding to periods of about 1.5 hr. These standing gravity waves produce temperature fluctuations that are amplified by a factor of 170 in the boron neutrino flux for the corresponding period, in consonance with the gravity modes. From current neutrino observations, we determine that the maximum temperature variation due to the gravity modes in the Sun's core is smaller than 5.8 × 10-4. This study clearly shows that due to their high sensitivity to the temperature, the 8 B neutrino flux time series is an excellent tool to determine the properties of gravity modes in the solar core. Moreover, if gravity mode footprints are discovered in the 8 B neutrino flux, this opens a new line of research to probe the physics of the solar core as non-standing gravity waves of higher periods cannot be directly detected by helioseismology but could leave their signature on boron neutrino or on other neutrino fluxes. Title: Picard SODISM, a Space Telescope to Study the Sun from the Middle Ultraviolet to the Near Infrared Authors: Meftah, M.; Hochedez, J. -F.; Irbah, A.; Hauchecorne, A.; Boumier, P.; Corbard, T.; Turck-Chièze, S.; Abbaki, S.; Assus, P.; Bertran, E.; Bourget, P.; Buisson, F.; Chaigneau, M.; Damé, L.; Djafer, D.; Dufour, C.; Etcheto, P.; Ferrero, P.; Hersé, M.; Marcovici, J. -P.; Meissonnier, M.; Morand, F.; Poiet, G.; Prado, J. -Y.; Renaud, C.; Rouanet, N.; Rouzé, M.; Salabert, D.; Vieau, A. -J. Bibcode: 2014SoPh..289.1043M Altcode: 2013arXiv1303.0731M The Solar Diameter Imager and Surface Mapper (SODISM) onboard the Picard space mission provides wide-field images of the photosphere and chromosphere of the Sun in five narrow bandpasses centered at 215.0, 393.37, 535.7, 607.1, and 782.2 nm. The Picard spacecraft was successfully launched on 15 June 2010 into a Sun-synchronous dawn-dusk orbit. The Picard space mission represents a European asset in collecting solar observations useful to improve Earth climatic models. The scientific payload consists of the SODISM imager and of two radiometers, SOlar VAriability Picard (SOVAP) and PREcision MOnitor Sensor (PREMOS), which measure the Total Solar Irradiance (TSI) and part of the Solar Spectral Irradiance (SSI). Title: Iron-group opacities in the envelopes of massive stars Authors: Le Pennec, Maëlle; Turck-Chièze, Sylvaine Bibcode: 2014IAUS..301..229L Altcode: β Cephei and SPB stars are pulsating stars for which the excitation of modes by the κ mechanism, due to the iron-group opacity peak, seems puzzling. We have first investigated the origins of the differences noticed between OP and OPAL iron and nickel opacity calculations (up to a factor 2), a fact which complicates the interpretation. To accomplish this task, new well-qualified calculations (SCO-RCG, HULLAC and ATOMIC) have been performed and compared to values of these tables, and most of the differences are now well understood. Next, we have exploited a dedicated experiment on chromium, iron and nickel, conducted at the LULI 2000 facilities. We found that, in the case of iron, detailed calculations (OP, ATOMIC and HULLAC) show good agreement, contrary to all of the non-detailed calculations. However, in the case of nickel, OP calculations show large discrepancies with the experiments but also with other codes. Thus, the opacity tables need to be revised in the thermodynamical conditions corresponding to the peak of the iron group. Consequently we study the evolution of this iron peak with changes in stellar mass, age, and metallicity to determine the relevant region where these tables should be revised. Title: Models of solar surface dynamics: impact on eigenfrequencies and radius Authors: Piau, L.; Collet, R.; Stein, R. F.; Trampedach, R.; Morel, P.; Turck-Chièze, S. Bibcode: 2014MNRAS.437..164P Altcode: 2013arXiv1309.7179P; 2013MNRAS.tmp.2547P We study the effects of different descriptions of the solar surface convection on the eigenfrequencies of p modes. 1D evolution calculations of the whole Sun and 3D hydrodynamic and magnetohydrodynamic simulations of the current surface are performed. These calculations rely on realistic physics. Averaged stratifications of the 3D simulations are introduced in the 1D solar evolution or in the structure models. The eigenfrequencies obtained are compared to those of 1D models relying on the usual phenomenologies of convection and to observations of the Michelson Doppler Imager instrument aboard the Solar Heliospheric Observatory (SoHO). We also investigate how the magnetic activity could change the eigenfrequencies and the solar radius, assuming that, 3 Mm below the surface, the upgoing plasma advects a 1.2 kG horizontal field. All models and observed eigenfrequencies are fairly close below 3 mHz. Above 3 mHz the eigenfrequencies of the phenomenological convection models are above the observed eigenfrequencies. The frequencies of the models based on the 3D simulations are slightly below the observed frequencies. Their maximum deviation is ≈3 μHz at 3 mHz but drops below 1 μHz at 4 mHz. Replacing the hydrodynamic by the magnetohydrodynamic simulation increases the eigenfrequencies. The shift is negligible below 2.2 mHz and then increases linearly with frequency to reach ≈1.7 μHz at 4 mHz. The impact of the simulated activity is a 14 mas shrinking of the solar layers near the optical depth unity. Title: Are We Entering a Period of Reduced Activity or a Grand Minima State? Authors: Simoniello, R.; Jain, K.; Tripathy, S. C.; Baldner, C. S.; Turck-Chièze, S.; Hill, F. Bibcode: 2013ASPC..478..167S Altcode: Solar cycle 23 has been characterized by an unpredicted deepest minimum in nearly a century, and solar cycle 24 has turned out to be 20% less strong than the previous cycle, against expectations. Are the current solar dynamics indicative that we might enter a period of reduced activity or even a Grand Minima state? To answer this question, we investigated the properties of the cyclic behavior of solar magnetic activity, characterized by the 11- and 2-year periodicity, the latter also known as the quasi-biennial periodicity (QBP). Recently it has been shown that the QBP signal might be the cycle period related to the quadrupolar component of the magnetic dynamo configuration. Observationally and theoretically, it has been shown that this component might play a key role over period of reduced activity by inducing a strong North-South asymmetry. We, therefore, wonder if the QBP signatures might be used as a precursor of solar magnetic activity. To this aim we used 17 years of Global Oscillation Network Group (GONG) observations to investigate the signatures and properties of the QBP in the dipolar and quadrupolar component of p-mode frequency shifts and in the even-order splitting coefficients of spherical degree ℓ = 0 - 120, as the latter are related to the magnetic field strength and oblateness. The observational findings seem to indicate that the QBP signal strength has been particularly strong over the ascending phase of solar cycle 23, but suddenly in 2003 became weaker and has remained weak over the ascending phase of solar cycle 24. We argue that the QBP, since 2003, suggested a week solar cycle 24 compared to cycle 23. Title: The Energetic Balance of the Sun and Stars Authors: Turck-Chièze, S.; Couvidat, S.; Gilles, D.; Le Pennec, M. Bibcode: 2013ASPC..479..485T Altcode: Helio- and asteroseismology keep delivering unprecedented views on solar and stellar interiors that were not anticipated twenty years ago. After five decades of detailed measurements, it is interesting to question the classical stellar evolution models in the light of these observations. This report focuses on two important aspects of stellar evolution: the conservation of energy and the transfer of energy in radiative zones. We discuss the reliability of the opacity coefficients provided by Opacity Project (OP) and OPAL tables by creating a stellar plasma in a laboratory and using new computer capabilities to perform more complex calculations. We then discuss the reliability of the energetic balance in solar-like stars in the light of both helioseismology and neutrino detections. We cannot exclude the possibility that a more detailed balance might be considered that takes into account the action of dynamical phenomena like meridional circulation, a fossil magnetic field generated during the initial stellar contraction or gravity waves along the Main Sequence phase. Title: Probing the radiative zones of stars: Present status and developments Authors: Turck-Chièze, S. Bibcode: 2013EAS....63..339T Altcode: Seismology of Sun and stars associated to precise solar neutrino detections reveals microscopic and macroscopic behaviors of radiative zones that were not anticipated by stellar modeling predictions. These results allow us to check the hypotheses of the equations used in stellar evolution for long. In this review, I list some of the problems which emerge from these confrontations both on the description of the Sun or solar-like stars and on the envelopes of intermediate-type stars, then I summarize the cases at least partly solved in using 3D MHD simulations, new opacity calculations and laboratory experiments. This review shows also how we hope to progress on the others inside our OPAC consortium or in using the coming detection of neutrino fluxes. Title: Iron and Nickel spectral opacity calculations in conditions relevant for pulsating stellar envelopes and experiments Authors: Gilles, D.; Turck-Chièze, S.; Busquet, M.; Thais, F.; Loisel, G.; Piau, L.; Ducret, J. E.; Blenski, T.; Blancard, C.; Cossé, P.; Faussurier, G.; Gilleron, F.; Pain, J. C.; Porcherot, Q.; Guzik, J. A.; Kilcrease, D. P.; Magee, N. H.; Harris, J.; Bastiani-Ceccotti, S.; Delahaye, F.; Zeippen, C. J. Bibcode: 2013EPJWC..5914003G Altcode: 2012arXiv1201.4692G Seismology of stars is strongly developing. To address this question we have formed an international collaboration, OPAC, to perform specific experimental measurements, compare opacity calculations, and improve the opacity calculations in stellar codes [1]. We consider the following opacity codes: SCO, CASSANDRA, STA, OPAS, LEDCOP, OP, SCO-RCG. Their comparison has shown large differences for Fe and Ni in equivalent conditions of envelopes of type II supernova precursors, temperatures between 15 and 40 eV and densities of a few mg/cm3 [2-4]. LEDCOP, OPAS, SCO-RCG structure codes and STA give similar results and differ from OP ones for the lower temperatures and for spectral interval values [3]. In this work we discuss the role of Configuration Interaction (CI) and the influence of the number of used configurations. We present and include in the opacity code comparisons new HULLAC-v9 calculations [5, 6] that include full CI. To illustrate the importance of this effect we compare different CI approximations (modes) available in HULLAC-v9 [7]. These results are compared to previous predictions and to experimental data. Differences with OP results are discussed. Title: The stellar opacities Authors: Turck-Chièze, S.; Gilles, D.; Gilleron, F.; Pain, J. C. Bibcode: 2013sf2a.conf..105T Altcode: Opacities are fundamental ingredients of stellar physics. Helioseismology and asteroseismology have put in evidence anomalies that could be attributed to an insufficient knowledge of the photon-plasma interactions. We work on a revision of this plasma physics in the conditions where the anomalies have been found: the region of the iron opacity peak near log T= 5.2 and the inner radiative region of Sun and solar-like stars. The international OPAC consortium performs new calculations, compares them and looks for the origin of their differences. In parallel, experimental campaigns are realized, others are in preparation to validate some conclusions on the reliability of the new proposed calculations. New tables for astrophysics will be performed in the framework of the ANR OPACITY and their influence on seismic observables will be studied. We explicit here the difficulty of the computations together with some computation resources. Title: Solar cycle and quasi-biennial variations in helioseismic frequencies Authors: Tripathy, Sushanta C.; Jain, Kiran; Simoniello, Rosaria; Hill, Frank; Turck-Chièze, Sylvaine Bibcode: 2013IAUS..294...73T Altcode: The prolonged period of solar minimum between cycles 23 and 24 has invoked a great deal of interest to understand the origin of the unusually low solar activity. Even though the origin of solar activity is believed to lie in the shear layer at the base of the convection zone, the analysis of helioseismic data seem to orientate us toward the near surface. In this context, we analyze the signature of the quasi-biennial periodicity seen in the oscillation frequencies which may provide additional constraints on the solar dynamo models. Title: Helioseismology with PICARD Authors: Corbard, T.; Salabert, D.; Boumier, P.; Appourchaux, T.; Hauchecorne, A.; Journoud, P.; Nunge, A.; Gelly, B.; Hochedez, J. F.; Irbah, A.; Meftah, M.; Renaud, C.; Turck-Chièze, S. Bibcode: 2013JPhCS.440a2025C Altcode: 2013arXiv1301.6940C PICARD is a CNES micro-satellite launched in June 2010 [17]. Its main goal is to measure the solar shape, total and spectral irradiance during the ascending phase of the activity cycle. The SODISM telescope onboard PICARD also allows us to conduct a program for helioseismology in intensity at 535.7 nm [5]. One-minute cadence low-resolution full images are available for a so-called medium-l program, and high-resolution images of the limb recorded every 2 minutes are used to study mode amplification near the limb in the perspective of g-mode search. First analyses and results from these two programs are presented here. Title: The Sun-as-a-star observations: GOLF & VIRGO on SoHO, and BiSON network Authors: García, R. A.; Davies, G. R.; Jiménez, A.; Ballot, J.; Mathur, S.; Salabert, D.; Chaplin, W. J.; Elsworth, Y.; Régulo, C.; Turck-Chièze, S. Bibcode: 2013JPhCS.440a2040G Altcode: 2013arXiv1301.6934G Sun-as-a-star observations are very important for the study of the conditions within the Sun and in particular for the deep interior where higher degree modes do not penetrate. They are also of significance in this era of dramatic advances in stellar asteroseismology as they are comparable to those measured in other stars by asteroseismic missions such as CoRoT, Kepler, and MOST. More than 17 years of continuous measurements of SoHO and more than 30 years of BiSON observations provide very long data sets of uninterrupted helioseismic observations. In this work, we discuss the present status of all these facilities that continue to provide state-of-the-art measurements and invaluable data to improve our knowledge of the deepest layers of the Sun and its structural changes during the activity cycle. Title: Solar Neutrino Physics Oscillations: Sensitivity to the Electronic Density in the Sun's Core Authors: Lopes, Ilídio; Turck-Chièze, Sylvaine Bibcode: 2013ApJ...765...14L Altcode: 2013arXiv1302.2791L Solar neutrinos coming from different nuclear reactions are now detected with high statistics. Consequently, an accurate spectroscopic analysis of the neutrino fluxes arriving on Earth's detectors becomes available, in the context of neutrino oscillations. In this work, we explore the possibility of using this information to infer the radial profile of the electronic density in the solar core. So, we discuss the constraints on the Sun's density and chemical composition that can be determined from solar neutrino observations. This approach constitutes an independent and alternative diagnostic to the helioseismic investigations already done. The direct inversion method, which we propose to obtain the radial solar electronic density profile, is almost independent of the solar model. Title: News from the opacity consortium OPAC Authors: Turck-Chièze, S.; Gilles, D. Bibcode: 2013EPJWC..4301003T Altcode: The international OPAC consortium (see list below) was formed three years ago. It is composed of astrophysicists, plasma physicists and experimentalists from different laboratories. This consortium examines specific opacity calculations used in stellar physics. They contribute to solve the problems suggested by the astrophysical community in performing new calculations and new experiments with laser installation. We show here the specific example of the iron opacity peak that plays an important role in the envelope of intermediate-mass and massive stars and we present our first conclusions on iron and nickel. Title: The Quasi-biennial Periodicity as a Window on the Solar Magnetic Dynamo Configuration Authors: Simoniello, R.; Jain, K.; Tripathy, S. C.; Turck-Chièze, S.; Baldner, C.; Finsterle, W.; Hill, F.; Roth, M. Bibcode: 2013ApJ...765..100S Altcode: 2012arXiv1210.6796S Manifestations of the solar magnetic activity through periodicities of about 11 and 2 years are now clearly seen in all solar activity indices. In this paper, we add information about the mechanism driving the 2-year period by studying the time and latitudinal properties of acoustic modes that are sensitive probes of the subsurface layers. We use almost 17 years of high-quality resolved data provided by the Global Oscillation Network Group to investigate the solar cycle changes in p-mode frequencies for spherical degrees l from 0 to 120 and 1600 μHz <=ν <= 3500 μHz. For both periodic components of solar activity, we locate the origin of the frequency shift in the subsurface layers and find evidence that a sudden enhancement in amplitude occurs in just the last few hundred kilometers. We also show that, in both cases, the size of the shift increases toward equatorial latitudes and from minimum to maximum solar activity, but, in agreement with previous findings, the quasi-biennial periodicity (QBP) causes a weaker shift in mode frequencies and a slower enhancement than that caused by the 11-year cycle. We compare our observational findings with the features predicted by different models, that try to explain the origin of this QBP and conclude that the observed properties could result from the beating between a dipole and quadrupole magnetic configuration of the dynamo. Title: Seismic diagnostics for transport of angular momentum in stars. I. Rotational splittings from the pre-main sequence to the red-giant branch Authors: Marques, J. P.; Goupil, M. J.; Lebreton, Y.; Talon, S.; Palacios, A.; Belkacem, K.; Ouazzani, R. -M.; Mosser, B.; Moya, A.; Morel, P.; Pichon, B.; Mathis, S.; Zahn, J. -P.; Turck-Chièze, S.; Nghiem, P. A. P. Bibcode: 2013A&A...549A..74M Altcode: 2012arXiv1211.1271M Context. Rotational splittings are currently measured for several main sequence stars and a large number of red giants with the space mission Kepler. This will provide stringent constraints on rotation profiles.
Aims: Our aim is to obtain seismic constraints on the internal transport and surface loss of the angular momentum of oscillating solar-like stars. To this end, we study the evolution of rotational splittings from the pre-main sequence to the red-giant branch for stochastically excited oscillation modes.
Methods: We modified the evolutionary code CESAM2K to take rotationally induced transport in radiative zones into account. Linear rotational splittings were computed for a sequence of 1.3 M⊙ models. Rotation profiles were derived from our evolutionary models and eigenfunctions from linear adiabatic oscillation calculations.
Results: We find that transport by meridional circulation and shear turbulence yields far too high a core rotation rate for red-giant models compared with recent seismic observations. We discuss several uncertainties in the physical description of stars that could have an impact on the rotation profiles. For instance, we find that the Goldreich-Schubert-Fricke instability does not extract enough angular momentum from the core to account for the discrepancy. In contrast, an increase of the horizontal turbulent viscosity by 2 orders of magnitude is able to significantly decrease the central rotation rate on the red-giant branch.
Conclusions: Our results indicate that it is possible that the prescription for the horizontal turbulent viscosity largely underestimates its actual value or else a mechanism not included in current stellar models of low mass stars is needed to slow down the rotation in the radiative core of red-giant stars. Title: Seismic comparison of the 11- and 2-year cycle signatures in the Sun Authors: Simoniello, R.; Jain, K.; Tripathy, S. C.; Turck-Chiéze, S.; Finsterle, W.; Roth, M. Bibcode: 2012AN....333.1018S Altcode: 2012arXiv1210.6182S The solar magnetic activity consists of two periodic components: the main cycle with a period of 11 yr and a shorter cycle with a period of ≈2 yr. The origin of this second periodicity is still not well understood. We use almost 15 years of long high-quality resolved data provided by the Global Oscillation Network Group (GONG) to investigate the solar cycle changes in p-mode oscillations with spherical degree ℓ= 0-120 and in the range of 1600 \muHz \le\nu\le 3500 \muHz. For both periodic components of solar magnetic activity our findings locate the origin of the frequency shift in the subsurface layers with a sudden enhancement in the amplitude of the shift in the last few hundred kilometers. We also show that the size of the shift increases towards equatorial latitudes and from minimum to maximum of solar activity. On the other hand, the signatures of the 2-yr cycle differ from the one of the 11-yr cycle in the magnitude of the shift, as the 2-yr cycle causes a weaker shift in mode frequencies and a slower enhancement in the last few hundred kilometers. Based on these findings we speculate that a possible physical mechanism behind the quasi biennial periodicity (QBP) could be the beating between different dynamo modes (dipole and quadrupole mode). Title: The Long-term Dynamics of the Solar Radiative Zone: New Results from the Solar and Heliospheric Observatory (SoHO) and Young Solar Analogs Authors: Turck-Chièze, S.; Couvidat, S.; Eff-Darwich, A.; Duez, V.; García, R. A.; Mathis, S.; Mathur, S.; Piau, L.; Salabert, D. Bibcode: 2012ASPC..462..366T Altcode: The Standard Solar Model (SSM) is no longer sufficient to interpret all the observations of the radiative zone obtained with the SoHO satellite. We recall our present knowledge of this internal region and compare recent results with models beyond the SSM assumptions. Then we discuss the missing processes and quantify some of them in using observations of young solar analogs to build a more realistic view of the Sun. This progress will be useful for understanding solar-like stars observed by CoRoT and Kepler. Title: Solar Global Oscillations of Low-Degree modes (GOLD): The Status of the Multi-channel Resonance Spectrometer GOLF-NG Authors: Turck-Chièze, S.; Carton, P. -H.; Barrière, J. -C.; Pallé, P. L.; Robillot, J. -M.; Ballot, J.; Chenus, A. -C.; Daniel-Thomas, P.; Delbart, A.; García, R. A.; Granelli, R.; Lahonde-Hamdoun, C.; Loiseau, D.; Mathur, S.; Piret, Y.; Salabert, D.; Simoniello, R.; Davies, G. R. Bibcode: 2012ASPC..462..240T Altcode: Low-degree pulsation modes are the best way to scrutinize stellar cores. They also provide, due to their intrinsic nature, a way to follow varying activity in important subsurface layers. Following difficulties encountered with the Solar and Heliospheric Observatory (SoHO) in 1998, we study a new design that improves the detection at low and high frequencies in comparison with the Global Oscillations at Low Frequency (GOLF) instrument. It is based on a substantial increase in the counting rates to get better photon statistics, and a reduction of the solar turbulent noise in measuring simultaneously the Doppler velocity at 6-7 heights in the strong sodium spectral line. A prototype, GOLF-NG (GOLF New Generation), has been built with numerous laboratory checks of the performance and in situ solar measurements at Tenerife in 2008 and 2010. All the required specifications are now achieved, and so GOLD can be prepared for space observations with balloons or satellites. The substantial improvements allow an improved detection of weak signals at different frequencies and information on activity indicators, as the Na D lines are sensitive to the magnetic field between photosphere and chromosphere. Title: Radiative Properties of Stellar Plasma Authors: Turck-Chièze, S.; Loisel, G.; Gilles, D.; Ducret, J. E.; Piau, L.; Blenski, T.; Poirier, M.; Thais, F.; Bastiani, S.; Blancard, C.; Busquet, M.; Caillaud, T.; Cossé, P.; Delahaye, F.; Faussurier, G.; Gilleron, F.; Guzik, J. A.; Harris, J. W.; Kilcrease, D. P.; Magee, N. H.; Pain, J. C.; Porcherot, Q.; Reverdin, C.; Silvert, V.; Villette, B.; Zeippen, C. Bibcode: 2012ASPC..462...95T Altcode: Opacity cross-section is an important ingredient of the secular evolution of stars. But calculation of the opacity coefficients is complex because of the partially ionized medium (Z ≤ 28) ion contributions to a mixture dominated by H/He. This implies that a very large number of lines must be considered to describe M or L transitions and produce the mean Rosseland values. Up to now the astrophysical community has greatly benefited from the work of the Los Alamos and Livermore teams and also from the academic Opacity Project tables producing also the corresponding energy spectra. Despite some opacity measurements performed at the beginning of the nineties and related progress, differences in the radiative forces and Rosseland mean values are still noticed with a real impact on asteroseismic interpretations or on diffusion in stellar models. So a new effort has been engaged these last three years to interpret the large number of data presently available with Solar and Heliospheric Observatory (SoHO), CoRoT and Kepler. High energy laser and Z-pinch facilities produce plasma in conditions of temperature and density useful for stellar conditions, and a new series of measurements have been performed recently. In parallel several new calculations have been done using OPAS, SCORCG, HULLAC codes to compare with new measurements and other codes on medium elements. The present consortium carefully checks the origin of the discrepancies between codes. We present and mention here some results and suggest a strategy for the years to come. Title: Solar-stellar astrophysics and dark matter Authors: Turck-Chièze, Sylvaine; Lopes, Ilídio Bibcode: 2012RAA....12.1107T Altcode: In this review, we recall how stars contribute to the search for dark matter and the specific role of the Sun. We describe a more complete picture of the solar interior that emerges from neutrino detections, gravity and acoustic mode measurements of the Solar and Heliospheric Observatory (SOHO) satellite, becoming a reference for the most common stars in the Universe. The Sun is a unique star in that we can observe directly the effect of dark matter. The absence of a signature related to Weakly Interacting Massive Particles (WIMPs) in its core disfavors a WIMP mass range below 12GeV. We give arguments to continue this search on the Sun and other promising cases. We also examine another dark matter candidate, the sterile neutrino, and infer the limitations of the classical structural equations. Open questions on the young Sun, when planets formed, and on its present internal dynamics are finally discussed. Future directions are proposed for the next decade: a better description of the solar core, a generalization to stars coming from seismic missions and a better understanding of the dynamics of our galaxy which are all crucial keys for understanding dark matter. Title: The quasi-biennial periodicity (QBP) in velocity and intensity helioseismic observations. The seismic QBP over solar cycle 23 Authors: Simoniello, R.; Finsterle, W.; Salabert, D.; García, R. A.; Turck-Chièze, S.; Jiménez, A.; Roth, M. Bibcode: 2012A&A...539A.135S Altcode: 2012arXiv1201.2773S
Aims: We looked for signatures of quasi-biennial periodicity (QBP) over different phases of solar cycle by means of acoustic modes of oscillation. Low-degree p-mode frequencies are shown to be sensitive to changes in magnetic activity due to the global dynamo. Recently there has been reported evidence of two-year variations in p-mode frequencies.
Methods: Long high-quality helioseismic data are provided by BiSON (Birmingham Solar Oscillation Network), GONG (Global Oscillation Network Group), GOLF (Global Oscillation at Low Frequency) and VIRGO (Variability of Solar IRradiance and Gravity Oscillation) instruments. We determined the solar cycle changes in p-mode frequencies for spherical degree ℓ = 0, 1, 2 with their azimuthal components in the frequency range 2.5 mHz ≤ ν ≤ 3.5 mHz.
Results: We found signatures of QBP at all levels of solar activity in the modes more sensitive to higher latitudes. The signal strength increases with latitude and the equatorial component also seems to be modulated by the 11-year envelope.
Conclusions: The persistent nature of the seismic QBP is not observed in the surface activity indices, where mid-term variations are found only from time to time and mainly in periods of high activity. This feature, together with the latitudinal dependence, provides more evidence of a mechanism that is almost independent and different from the one that brings the active regions up to the surface. Therefore, these findings can be used to provide more constraints on dynamo models that consider a further cyclic component on top of the 11-year cycle. Title: Interaction of configuration in spectral opacity calculations for stellar physics Authors: Gilles, D.; Turck-Chièze, S.; Busquet, M.; Thais, F.; Loisel, G.; Piau, L.; Ducret, J. E.; Blenski, T.; Poirier, M.; Blancard, C.; Cossé, P.; Faussurier, G.; Gilleron, F.; Pain, J. C.; Guzik, J. A.; Kilcrease, D. P.; Magee, N. H.; Harris, J.; Bastiani-Ceccotti, S.; Delahaye, F.; Zeippen, C. J. Bibcode: 2012EAS....58...51G Altcode: We discuss the role of Configuration Interaction (CI) and the influence of the number of configurations taken into account in the calculations of nickel and iron spectral opacities provided by the OPAC international collaboration, including statistical approaches (SCO, CASSANDRA, STA), detailed accounting (OPAS, LEDCOP, OP, HULLAC-v9) or hybrid method (SCO-RCG). Opacity calculations are presented for a temperature T of 27.3 eV and a density of 3.4 mg/cm3, conditions relevant for pulsating stellar envelopes. Title: First Study of Dark Matter Properties with Detected Solar Gravity Modes and Neutrinos Authors: Turck-Chièze, S.; García, R. A.; Lopes, I.; Ballot, J.; Couvidat, S.; Mathur, S.; Salabert, D.; Silk, J. Bibcode: 2012ApJ...746L..12T Altcode: We derive new limits on the cold dark matter properties for weakly interacting massive particles (WIMPs), potentially trapped in the solar core by using for the first time the central temperature constrained by boron neutrinos and the central density constrained by the dipolar gravity modes detected with the Global Oscillations at Low Frequency/Solar Helioseismic Observatory instrument. These detections disfavor the presence of non-annihilating WIMPs for masses <=10 GeV and spin dependent cross-sections >5 × 10-36 cm2 in the solar core but cannot constrain WIMP annihilation models. We suggest that in the coming years helio- and asteroseismology will provide complementary probes of dark matter. Title: Seismology of Sun and stars and related opacity laboratory measurements Authors: Turck-Chièze, S. Bibcode: 2012EAS....58...43T Altcode: CNES, ESA and NASA have invested in helioseismic and asteroseismic disciplines for 2 decades with SoHO (1995-2015), COROT (2006-2013), KEPLER (2009-2014), PICARD (2010-2013) and SDO (2010-2015). These missions focus on the stellar internal dynamics and their influence of neighboring planets. Progress along this path requires that the microscopic physics is well under control, but several seismic probes indicate some discrepancies which justify new investigations of the energy transport in radiative zones of the Sun and massive stars, despite strong efforts dedicated to reaction rates, screening, equation of state and opacity coefficients between 1990 and 2000. We describe here how the OPAC consortium tackles the complex problem of photon absorption by matter both theoretically and experimentally, by using high energy laser facilities. These studies might be also useful for other disciplines like fusion for energy and X-ray spectroscopy astronomy. Title: What we know and do not know about neutrino production in stars Authors: Turck-Chièze, Sylvaine Bibcode: 2011NuPhS.221..292T Altcode: This review summarizes the necessary ingredients for determining the neutrino production rates in stars. Then the case of the Sun is studying. A detailed comparison between solar neutrino predictions and each neutrino detection shows the interest of the seismic model versus standard model. After the determination of θ12, Δ and the inclusion of electronic neutrino transformation, the global agreement is a noticeable success with nevertheless some identified questions. The second part of the review is dedicated to the important lacks in solar and stellar modelling and to the way we are presently attacking the different problems. Such situation encourages to pursue the effort on stellar neutrino detections and neutrino predictions, astrophysics modelling with evident consequences for stellar evolution, supernovae explosion and neutrino properties. Title: Comparison of Fe and Ni opacity calculations for a better understanding of pulsating stellar envelopes Authors: Gilles, D.; Turck-Chièze, S.; Loisel, G.; Piau, L.; Ducret, J. -E.; Poirier, M.; Blenski, T.; Thais, F.; Blancard, C.; Cossé, P.; Faussurier, G.; Gilleron, F.; Pain, J. C.; Porcherot, Q.; Guzik, J. A.; Kilcrease, D. P.; Magee, N. H.; Harris, J.; Busquet, M.; Delahaye, F.; Zeippen, C. J.; Bastiani-Ceccotti, S. Bibcode: 2011HEDP....7..312G Altcode: 2011HEDP....7..312.; 2012arXiv1201.6245G Opacity is an important ingredient of the evolution of stars. The calculation of opacity coefficients is complicated by the fact that the plasma contains partially ionized heavy ions that contribute to opacity dominated by H and He. Up to now, the astrophysical community has greatly benefited from the work of the contributions of Los Alamos [1], Livermore [2] and the Opacity Project (OP) [3]. However unexplained differences of up to 50% in the radiative forces and Rosseland mean values for Fe have been noticed for conditions corresponding to stellar envelopes. Such uncertainty has a real impact on the understanding of pulsating stellar envelopes, on the excitation of modes, and on the identification of the mode frequencies. Temperature and density conditions equivalent to those found in stars can now be produced in laboratory experiments for various atomic species. Recently the photo-absorption spectra of nickel and iron plasmas have been measured during the LULI 2010 campaign, for temperatures between 15 and 40 eV and densities of ∼3 mg/cm3. A large theoretical collaboration, the "OPAC", has been formed to prepare these experiments. We present here the set of opacity calculations performed by eight different groups for conditions relevant to the LULI 2010 experiment and to astrophysical stellar envelope conditions. Title: Simulations of the solar atmosphere and solar limbs Authors: Piau, L.; Stein, R. F.; Melo, S.; Turck-Chièze, S.; Thuillier, G.; Hauchecorne, A. Bibcode: 2011sf2a.conf..407P Altcode: We perform simulations of the solar atmosphere either using the 1D hydrostatic code Atlas12 or the 3D (magneto)hydrodynamic code Stagger. The former numerical tool relies on a phenomenology of convection whereas the later one addresses the surface convection directly and accounts for its dynamical effects. Once the average atmosphere stratification is obtained it is used to perform radiative transfer at speficic wavelengths in order to compute the solar limb darkening. We report a ≈ 60 mas shift between inflection point positions of limb profiles computed from 1D and 3D models. This is due to turbulent support present in 3D simulations but not 1D. We further report a slight decrease of the turbulent support when a moderate magnetic field is included in the simulation which suggests that the solar radius should be anti-correlated with the solar activity cycle. Title: Main lessons from GOLF/SOHO instrument on dynamics of the radiative zone, fundamental physics and energetics Authors: Turck-Chièze, S.; García, R. A.; Piau, L.; Couvidat, S. Bibcode: 2011sf2a.conf..257T Altcode: The GOLF instrument aboard SoHO has reached its main objectives and reveals its power to constrain fundamental physics, energetics and dynamics of the radiative zone. The Standard Solar Model (SSM) is no more sufficient to interpret all the seismic observations of the solar radiative zone. We confront the main results of GOLF to models beyond the SSM assumptions. We discuss the missing processes and quantify some of them to build a more realistic view of our star. Present works on GOLF instrument are now turned on its capability to follow the solar activity and on a tentative to detect more gravity modes. All the results are useful for solar-like stars observed by COROT and KEPLER. Title: Radiative properties of stellar plasmas and open challenges Authors: Turck-Chièze, S.; Loisel, G.; Gilles, D.; Piau, L.; Blancard, C.; Blenski, T.; Busquet, M.; Caillaud, T.; Cossé, P.; Delahaye, F.; Faussurier, G.; Fariaut, J.; Gilleron, F.; Guzik, J. A.; Harris, J.; Kilcrease, D. P.; Magee, N. H.; Pain, J. C.; Porcherot, Q.; Poirier, M.; Soullier, G.; Zeippen, C. J.; Bastiani-Ceccotti, S.; Reverdin, C.; Silvert, V.; Thais, F.; Villette, B. Bibcode: 2011Ap&SS.336..103T Altcode: 2011Ap&SS.tmp..367T; 2011Ap&SS.tmp..247T; 2011arXiv1101.1170T The lifetime of solar-like stars, the envelope structure of more massive stars, and stellar acoustic frequencies largely depend on the radiative properties of the stellar plasma. Up to now, these complex quantities have been estimated only theoretically. The development of the powerful tools of helio- and astero- seismology has made it possible to gain insights on the interiors of stars. Consequently, increased emphasis is now placed on knowledge of the monochromatic opacity coefficients. Here we review how these radiative properties play a role, and where they are most important. We then concentrate specifically on the envelopes of β Cephei variable stars. We discuss the dispersion of eight different theoretical estimates of the monochromatic opacity spectrum and the challenges we need to face to check these calculations experimentally. Title: From Sun to Stars: Macroscopic and Microscopic processes for solar-like stars Authors: Turck-Chièze, Sylvaine Bibcode: 2011iasa.confE..15T Altcode: No abstract at ADS Title: The long term dynamics of the solar radiative zone associated to new results from SoHO and young solar analogs Authors: Turck-Chieze, Sylvaine; Couvidat, Sebastien; Eff-Darwich, Antonio; Duez, Vincent; Garcia, Rafael A.; Mathis, Stephane; Mathur, Savita; Piau, Laurent; Salabert, David Bibcode: 2011arXiv1109.4125T Altcode: The Standard Solar Model (SSM) is no more sufficient to interpret all the observations of the radiative zone obtained with the SoHO satellite. We recall our present knowledge of this internal region and compare the recent results to models beyond the SSM assumptions. Then we discuss the missing processes and quantify some of them in using young analog observations to build a more realistic view of our star. This progress will be useful for solar-like stars observed by COROT and KEPLER. Title: Solar neutrinos, helioseismology and the solar internal dynamics Authors: Turck-Chièze, Sylvaine; Couvidat, Sébastien Bibcode: 2011RPPh...74h6901T Altcode: 2010arXiv1009.0852T Neutrinos are fundamental particles ubiquitous in the Universe and whose properties remain elusive despite more than 50 years of intense research activity. This review illustrates the importance of solar neutrinos in astrophysics, nuclear physics and particle physics. After a description of the historical context, we remind the reader of the noticeable properties of these particles and of the stakes of the solar neutrino puzzle. The standard solar model triggered persistent efforts in fundamental physics to predict the solar neutrino fluxes, and its constantly evolving predictions have been regularly compared with the detected neutrino signals. Anticipating that this standard model could not reproduce the internal solar dynamics, a seismic solar model was developed which enriched theoretical neutrino flux predictions with in situ observation of acoustic and gravity waves propagating in the Sun. This seismic model contributed to the stabilization of the neutrino flux predictions. This review recalls the main historical steps, from the pioneering Homestake mine experiment and the GALLEX-SAGE experiments capturing the first proton-proton neutrinos. It emphasizes the importance of the SuperKamiokande and SNO detectors. Both experiments demonstrated that the solar-emitted electron neutrinos are partially transformed into other neutrino flavors before reaching the Earth. This sustained experimental effort opens the door to neutrino astronomy, with long-base lines and underground detectors. The success of BOREXINO in detecting the 7Be neutrino signal alone instills confidence in physicists' ability to detect each neutrino source separately. It justifies the building of a new generation of detectors to measure the entire solar neutrino spectrum in greater detail, as well as supernova neutrinos. A coherent picture has emerged from neutrino physics and helioseismology. Today, new paradigms take shape in these two fields: neutrinos are massive particles, but their masses are still unknown, and the research on the solar interior focuses on the dynamical aspects and on the signature of dark matter. The magnetic moment of the neutrino begins to be an actor in stellar evolution. The third part of the review is dedicated to this prospect. The understanding of the crucial role of both rotation and magnetism in solar physics benefits from SoHO, SDO and PICARD space observations, and from a new prototype, GOLF-NG. The magnetohydrodynamical view of the solar interior is a new way of understanding the impact of the Sun on the Earth's environment and climate. For now, the particle and stellar challenges seem decoupled, but this is only a superficial appearance. The development of asteroseismology—with the COROT and KEPLER spacecraft—and of neutrino physics will both contribute to improvements in our understanding of, for instance, supernova explosions. This shows the far-reaching impact of neutrino and stellar astronomy. Title: The Solar Energetic Balance Revisited by Young Solar Analogs, Helioseismology, and Neutrinos Authors: Turck-Chièze, Sylvaine; Piau, Laurent; Couvidat, Sébastien Bibcode: 2011ApJ...731L..29T Altcode: 2011arXiv1103.2620T The energetic balance of the standard solar model (SSM) results from equilibrium between nuclear energy production, energy transfer, and photospheric emission. In this Letter, we give an order of magnitude of several percent for the loss of energy in kinetic energy, magnetic energy, and X-ray or UV radiation during the entire solar lifetime from the observations of the present Sun. We also estimate the loss of mass from the observations of young solar analogs, which could reach up to 30%. We deduce new models of the present Sun, their associated neutrino fluxes, and internal sound-speed profile. This approach sheds quantitative lights on the disagreement between the sound speed obtained by helioseismology and the sound speed derived from the SSM including the updated photospheric CNO abundances, based on recent observations. We conclude that about 20% of the present discrepancy could come from the incorrect description of the early phases of the Sun, its activity, its initial mass, and mass-loss history. This study has obvious consequences on the solar system formation and the early evolution of the closest planets. Title: How the solar dynamics can influence the Sun-Earth medium term relationship Authors: Turck-Chièze, Sylvaine; Lefebvre, Sandrine Bibcode: 2011JASTP..73..251T Altcode: We recall how the Sun is introduced in the present climatic models and discuss why the solar standard model (SSM) framework is insufficient to describe the Sun-Earth medium term relationship. We then report on the different sources of variability. The SoHO mission allows a comparison between two successive solar minima and puts new constraints on the internal rotation profile. The coming space missions SDO and PICARD will add crucial information on internal circulations and on the superficial asphericity. The interplay between the solar dynamics and terrestrial atmospheric models is in its infancy, it calls for medium term uninterrupted solar observations which will take benefit of a formation flying concept. Title: New insights on the solar core Authors: García, R. A.; Salabert, D.; Ballot, J.; Eff-Darwich, A.; Garrido, R.; Jiménez, A.; Mathis, S.; Mathur, S.; Moya, A.; Pallé, P. L.; Régulo, C.; Sato, K.; Suárez, J. C.; Turck-Chièze, S. Bibcode: 2011JPhCS.271a2046G Altcode: 2010arXiv1012.0506G Since the detection of the asymptotic properties of the dipole gravity modes in the Sun, the quest to find individual gravity modes has continued. An extensive and deeper analysis of 14 years of continuous GOLF/SoHO observational data, unveils the presence of a pattern of peaks that could be interpreted as individual dipole gravity modes in the frequency range between 60 and 140 microHz, with amplitudes compatible with the latest theoretical predictions. By collapsing the power spectrum we have obtained a quite constant splitting for these patterns in comparison to regions where no g modes were expected. Moreover, the same technique applied to simultaneous VIRGO/SoHO data unveils some common signals between the power spectra of both instruments. Thus, we are able to identify and characterize individual g modes with their central frequencies, amplitudes and splittings allowing to do seismic inversions of the rotation profile inside the solar core. These results open a new ligh t on the physics and dynamics of the solar deep core. Title: The dynamics of the radiative zone of the Sun Authors: Turck-Chièze, S.; Couvidat, S.; Duez, V.; Mathis, S.; Marques, J.; Palacios, A.; Piau, L. Bibcode: 2011JPhCS.271a2044T Altcode: 2011arXiv1101.1185T Helioseismology puts strong constraints on the internal sound speed and on the rotation profile in the radiative zone. Young stars of solar type are more active and faster rotators than the Sun. So we begin to build models which include different rotation histories and compare the results with all the solar observations. The profiles of the rotation we get have interesting consequence for the introduction of magnetic field in the radiative zone. We discuss also the impact of mass loss deduced from measured flux of young stars. We deduce from these comparisons some quantitative effect of the dynamical processes (rotation, magnetic field and mass loss) of these early stages on the present sound speed and density. We show finally how we can improve our present knowledge of the radiative zone with PICARD and GOLFNG. Title: Theoretical and experimental activities on opacities for a good interpretation of seismic stellar probes Authors: Turck-Chièze, S.; Loisel, G.; Gilles, D.; Thais, F.; Bastiani, S.; Blancard, C.; Busquet, M.; Caillaud, T.; Cosse, P.; Blenski, T.; Delahaye, F.; Educret, J.; Faussurier, G.; Gilleron, F.; Guzik, J.; Harris, J. W.; Kilcrease, D. P.; Magee, N. H.; Piau, L.; Pain, J. C.; Poirier, M.; Porcherot, Q.; Reverdin, C.; Silvert, V.; Villette, B.; Zeippen, C. Bibcode: 2011JPhCS.271a2035T Altcode: 2011arXiv1101.1182T Opacity calculations are basic ingredients of stellar modelling. They play a crucial role in the interpretation of acoustic modes detected by SoHO, COROT and KEPLER. In this review we present our activities on both theoretical and experimental sides. We show new calculations of opacity spectra and comparisons between eight groups who produce opacity spectra calculations in the domain where experiments are scheduled. Real differences are noticed with real astrophysical consequences when one extends helioseismology to cluster studies of different compositions. Two cases are considered presently: (1) the solar radiative zone and (2) the beta Cephei envelops. We describe how our experiments are performed and new preliminary results on nickel obtained in the campaign 2010 at LULI 2000 at Polytechnique. Title: Towards a detection of individual g modes in the Sun Authors: Garcia, R. A.; Ballot, J.; Eff-Darwich, A.; Garrido, R.; Jimenez, A.; Mathis, S.; Mathur, S.; Moya, A.; Palle, P. L.; Regulo, C.; Salabert, D.; Suarez, J. C.; Turck-Chieze, S. Bibcode: 2010arXiv1007.4445G Altcode: Since the detection of the asymptotic properties of the dipole gravity modes in the Sun, the quest to find the individual gravity modes has continued. A deeper analysis of the GOLF/SoHO data unveils the presence of a pattern of peaks that could be interpreted as individual dipole gravity modes. The computed collapsed spectrum -around these candidate modes- uncovers the presence of a quasi constant frequency splitting, in contrast with regions where no g modes are expected in which the collapsogram gives random results. Besides, the same technique applied to VIRGO/SoHO unveils some common signals between both power spectra. Thus, we can identify and characterize the modes, for example, with their central frequency and splittings. This would open the path towards new investigations to better constrain the solar core. Title: Towards a New Formation Flying Solar Coronagraph Authors: Lamy, P.; Vives, S.; Curdt, W.; Dame, L.; Davila, J.; Defise, J. M.; Fineschi, S.; Heinzel, P.; Kuzin, S.; Schmutz, W.; Tsinganos, K.; Turck-Chieze, S.; Zhukov, A. Bibcode: 2010ASPC..424...15L Altcode: We briefly describe an investigation aiming at the development of a giant solar coronagraph instrument onboard of two satellites, separated by about 150 m in formation flight for the detailed observation of the solar coronal plasma. The European Space Agency (ESA) has selected this instrument as the only payload onboard the Proba 3 satellites which will be launched in 2013. The Greek team is developing the command control board of the coronagraph. Title: Seismic and Dynamical Solar Models. I. The Impact of the Solar Rotation History on Neutrinos and Seismic Indicators Authors: Turck-Chièze, S.; Palacios, A.; Marques, J. P.; Nghiem, P. A. P. Bibcode: 2010ApJ...715.1539T Altcode: 2010arXiv1004.1657T Solar activity and helioseismology show the limitation of the standard solar model and call for the inclusion of dynamical processes in both convective and radiative zones. In this paper, we concentrate on the radiative zone. We first recall the sensitivity of boron neutrinos to the microscopic physics included in solar standard and seismic models. We confront the neutrino predictions of the seismic model with all the detected neutrino fluxes. Then, we compute new models of the Sun including a detailed transport of angular momentum and chemicals due to internal rotation that includes meridional circulation and shear-induced turbulence. We use two stellar evolution codes: CESAM and STAREVOL to estimate the different terms. We follow three temporal evolutions of the internal rotation which differ by their initial conditions: very slow, moderate, and fast rotation, with magnetic braking at the arrival on the main sequence for the last two. We find that the meridional velocities in the present solar radiative zone are extremely small in comparison with those of the convective zone (smaller than 10-6 cm s-1 instead of m s-1). All models lead to a radial differential rotation profile in the radiative zone but with a significantly different contrast. We compare these profiles to the presumed solar internal rotation and show that if meridional circulation and shear turbulence were the only mechanisms transporting angular momentum within the Sun, a rather slow rotation in the young Sun is favored. We confirm the small influence of the transport by rotation on the sound speed profile but its potential impact on the chemicals in the transition region between radiation and convective zones. These models are physically more representative of the real Sun than the standard or seismic solar models but a high initial rotation, as has been considered previously, increases the disagreement with neutrinos and the sound speed in the radiative zone. This present work pushes us to pursue the inclusion of the other dynamical processes to better reproduce the observed solar profile in the whole radiative zone and to better describe the young active Sun. We also need to get a better knowledge of solar gravity mode splittings to use their constraints. Title: A Multi-Site Campaign to Measure Solar-Like Oscillations in Procyon. II. Mode Frequencies Authors: Bedding, Timothy R.; Kjeldsen, Hans; Campante, Tiago L.; Appourchaux, Thierry; Bonanno, Alfio; Chaplin, William J.; Garcia, Rafael A.; Martić, Milena; Mosser, Benoit; Butler, R. Paul; Bruntt, Hans; Kiss, László L.; O'Toole, Simon J.; Kambe, Eiji; Ando, Hiroyasu; Izumiura, Hideyuki; Sato, Bun'ei; Hartmann, Michael; Hatzes, Artie; Barban, Caroline; Berthomieu, Gabrielle; Michel, Eric; Provost, Janine; Turck-Chièze, Sylvaine; Lebrun, Jean-Claude; Schmitt, Jerome; Bertaux, Jean-Loup; Benatti, Serena; Claudi, Riccardo U.; Cosentino, Rosario; Leccia, Silvio; Frandsen, Søren; Brogaard, Karsten; Glowienka, Lars; Grundahl, Frank; Stempels, Eric; Arentoft, Torben; Bazot, Michaël; Christensen-Dalsgaard, Jørgen; Dall, Thomas H.; Karoff, Christoffer; Lundgreen-Nielsen, Jens; Carrier, Fabien; Eggenberger, Patrick; Sosnowska, Danuta; Wittenmyer, Robert A.; Endl, Michael; Metcalfe, Travis S.; Hekker, Saskia; Reffert, Sabine Bibcode: 2010ApJ...713..935B Altcode: 2010arXiv1003.0052B We have analyzed data from a multi-site campaign to observe oscillations in the F5 star Procyon. The data consist of high-precision velocities that we obtained over more than three weeks with 11 telescopes. A new method for adjusting the data weights allows us to suppress the sidelobes in the power spectrum. Stacking the power spectrum in a so-called échelle diagram reveals two clear ridges, which we identify with even and odd values of the angular degree (l = 0 and 2, and l = 1 and 3, respectively). We interpret a strong, narrow peak at 446 μHz that lies close to the l = 1 ridge as a mode with mixed character. We show that the frequencies of the ridge centroids and their separations are useful diagnostics for asteroseismology. In particular, variations in the large separation appear to indicate a glitch in the sound-speed profile at an acoustic depth of ~1000 s. We list frequencies for 55 modes extracted from the data spanning 20 radial orders, a range comparable to the best solar data, which will provide valuable constraints for theoretical models. A preliminary comparison with published models shows that the offset between observed and calculated frequencies for the radial modes is very different for Procyon than for the Sun and other cool stars. We find the mean lifetime of the modes in Procyon to be 1.29+0.55 -0.49 days, which is significantly shorter than the 2-4 days seen in the Sun. Title: The Asteroseismic Potential of Kepler: First Results for Solar-Type Stars Authors: Chaplin, W. J.; Appourchaux, T.; Elsworth, Y.; García, R. A.; Houdek, G.; Karoff, C.; Metcalfe, T. S.; Molenda-Żakowicz, J.; Monteiro, M. J. P. F. G.; Thompson, M. J.; Brown, T. M.; Christensen-Dalsgaard, J.; Gilliland, R. L.; Kjeldsen, H.; Borucki, W. J.; Koch, D.; Jenkins, J. M.; Ballot, J.; Basu, S.; Bazot, M.; Bedding, T. R.; Benomar, O.; Bonanno, A.; Brandão, I. M.; Bruntt, H.; Campante, T. L.; Creevey, O. L.; Di Mauro, M. P.; Doǧan, G.; Dreizler, S.; Eggenberger, P.; Esch, L.; Fletcher, S. T.; Frandsen, S.; Gai, N.; Gaulme, P.; Handberg, R.; Hekker, S.; Howe, R.; Huber, D.; Korzennik, S. G.; Lebrun, J. C.; Leccia, S.; Martic, M.; Mathur, S.; Mosser, B.; New, R.; Quirion, P. -O.; Régulo, C.; Roxburgh, I. W.; Salabert, D.; Schou, J.; Sousa, S. G.; Stello, D.; Verner, G. A.; Arentoft, T.; Barban, C.; Belkacem, K.; Benatti, S.; Biazzo, K.; Boumier, P.; Bradley, P. A.; Broomhall, A. -M.; Buzasi, D. L.; Claudi, R. U.; Cunha, M. S.; D'Antona, F.; Deheuvels, S.; Derekas, A.; García Hernández, A.; Giampapa, M. S.; Goupil, M. J.; Gruberbauer, M.; Guzik, J. A.; Hale, S. J.; Ireland, M. J.; Kiss, L. L.; Kitiashvili, I. N.; Kolenberg, K.; Korhonen, H.; Kosovichev, A. G.; Kupka, F.; Lebreton, Y.; Leroy, B.; Ludwig, H. -G.; Mathis, S.; Michel, E.; Miglio, A.; Montalbán, J.; Moya, A.; Noels, A.; Noyes, R. W.; Pallé, P. L.; Piau, L.; Preston, H. L.; Roca Cortés, T.; Roth, M.; Sato, K. H.; Schmitt, J.; Serenelli, A. M.; Silva Aguirre, V.; Stevens, I. R.; Suárez, J. C.; Suran, M. D.; Trampedach, R.; Turck-Chièze, S.; Uytterhoeven, K.; Ventura, R.; Wilson, P. A. Bibcode: 2010ApJ...713L.169C Altcode: 2010arXiv1001.0506C We present preliminary asteroseismic results from Kepler on three G-type stars. The observations, made at one-minute cadence during the first 33.5 days of science operations, reveal high signal-to-noise solar-like oscillation spectra in all three stars: about 20 modes of oscillation may be clearly distinguished in each star. We discuss the appearance of the oscillation spectra, use the frequencies and frequency separations to provide first results on the radii, masses, and ages of the stars, and comment in the light of these results on prospects for inference on other solar-type stars that Kepler will observe. Title: Concluding remarks on solar and stellar activities and related planets Authors: Turck-Chièze, Sylvaine Bibcode: 2010IAUS..264..507T Altcode: 2009arXiv0911.4740T The symposium has shown the dynamism of this rapidly evolving discipline. I shall concentrate here on some highlights and some complementary informations. I conclude on open questions with some perspectives on solar & stellar activity and related planets. Title: Effect of a fossil magnetic field on the structure of a young Sun Authors: Duez, V.; Mathis, S.; Turck-Chièze, S. Bibcode: 2010MNRAS.402..271D Altcode: 2009MNRAS.tmp.1928D; 2009arXiv0911.0788D We study the impact of a fossil magnetic field on the physical quantities which describe the structure of a young Sun of 500 Myr. We consider for the first time a non-force-free field composed of a mixture of poloidal and toroidal magnetic fields and propose a specific configuration to illustrate our purpose. In this paper, we estimate the relative role of the different terms which appear in the modified stellar structure equations. We note that the Lorentz tension plays a non-negligible role in addition to the magnetic pressure. This is interesting because most of the previous stellar evolution codes ignored that term and the geometry of the field. The solar structure perturbations are, as already known, small and consequently we have been able to estimate each term semi-analytically. We develop a general treatment to calculate the global modification of the structure and of the energetic balance. We also estimate the gravitational multipolar moments associated with the presence of a fossil large-scale magnetic field in radiative zone. The values given for the young Sun help the future implementation in stellar evolution codes. This work can be repeated for any other field configuration and prepares the achievement of a solar magnetohydrodynamic model where we will follow the transport of such field on secular time-scales and the associated transport of momentum and chemicals. The described method will be applied at the present Sun and the results will be compared with the coming balloon or space measurements. Title: The quest for the solar g modes Authors: Appourchaux, T.; Belkacem, K.; Broomhall, A. -M.; Chaplin, W. J.; Gough, D. O.; Houdek, G.; Provost, J.; Baudin, F.; Boumier, P.; Elsworth, Y.; García, R. A.; Andersen, B. N.; Finsterle, W.; Fröhlich, C.; Gabriel, A.; Grec, G.; Jiménez, A.; Kosovichev, A.; Sekii, T.; Toutain, T.; Turck-Chièze, S. Bibcode: 2010A&ARv..18..197A Altcode: 2010A&ARv.tmp....1A; 2009arXiv0910.0848A Solar gravity modes (or g modes)—oscillations of the solar interior on which buoyancy acts as the restoring force—have the potential to provide unprecedented inference on the structure and dynamics of the solar core, inference that is not possible with the well-observed acoustic modes (or p modes). The relative high amplitude of the g-mode eigenfunctions in the core and the evanesence of the modes in the convection zone make the modes particularly sensitive to the physical and dynamical conditions in the core. Owing to the existence of the convection zone, the g modes have very low amplitudes at photospheric levels, which makes the modes extremely hard to detect. In this article, we review the current state of play regarding attempts to detect g modes. We review the theory of g modes, including theoretical estimation of the g-mode frequencies, amplitudes and damping rates. Then we go on to discuss the techniques that have been used to try to detect g modes. We review results in the literature, and finish by looking to the future, and the potential advances that can be made—from both data and data-analysis perspectives—to give unambiguous detections of individual g modes. The review ends by concluding that, at the time of writing, there is indeed a consensus amongst the authors that there is currently no undisputed detection of solar g modes. Title: Interior and Exterior Clues of Solar Activity Authors: Turck-Chièze, S.; Brun, A. S.; Duez, V.; García, R. A.; Mathis, S.; Piau, L.; Salabert, D.; Pallé, P. L.; Jiménez-Reyes, S. J.; Mathur, S.; Simoniello, R.; Robillot, J. M. Bibcode: 2010ASSP...19..368T Altcode: 2010mcia.conf..368T Two research paths are described to obtain better understanding of the origin of global solar activity. First, observations with a multichannel resonant spectrometer may reveal the dynamics of the solar core, the tachocline, and the temporal evolution of activity between the photosphere and chromosphere. Such new observations will deliver constraints for 3D simulations of solar activity. Second, we examine the ab-initio introduction of a non-force-free field expressed in spherical harmonics into the solar structure equations and estimate its impact on the inner and subsurface layers, its time evolution, and its role in angular momentum transport. Title: ASPIICS / PROBA-3: a formation flying externally-occulted giant coronagraph mission Authors: Lamy, Philippe; Damé, Luc; Curdt, W.; Davila, J.; Defise, J. M.; Fineschi, S.; Heinzel, P.; Howard, R.; Kuzin, S.; Schmutz, W.; Tsinganos, K.; Turck-Chièze, S.; Zhukov, A. Bibcode: 2010cosp...38.2858L Altcode: 2010cosp.meet.2858L Classical externally-occulted coronagraphs are presently limited in their performances by the distance between the external occulter and the front objective. The diffraction fringe from the occulter and the vignetted pupil which degrades the spatial resolution prevent useful observa-tions of the white light corona inside typically 2-2.5 Rsun. Formation flying offers an elegant solution to these limitations and allows conceiving giant, externally-occulted coronagraphs us-ing a two-component space system with the external occulter on one spacecraft and the optical instrument on the other spacecraft at distances of hundred meters. Such an instrument has just been selected by ESA to fly (by the end of 2013) on its PROBA-3 mission, presently in phase B, to demonstrate formation flying. It will perform both high spatial resolution imaging of the solar corona as well as 2-dimensional spectroscopy of several emission lines (in partic-ular the forbidden line of FeXIV at 530.285 nm) from the coronal base out to 3 Rsun using a Fabry-Perot interferometer. The classical design of an externally-occulted coronagraph is adapted to the formation flying configuration allowing the detection of the very inner corona as close as 0.05 Rsun from the solar limb. By tuning the position of the occulter spacecraft, it may even be possible to try reaching the chromosphere and the upper part of the spicules. ASPIICS/PROBA-3 mission, payload and scientific objectives are detailed. Title: Multi-spacecraft observation of a magnetic cloud Authors: de Lucas, Aline; Dal Lago, Alisson; Schwenn, Rainer; Clúa de Gonzalez, Alicia L.; Marsch, Eckart; Lamy, Philippe; Damé, Luc; Curdt, W.; Davila, J.; Defise, J. M.; Fineschi, S.; Heinzel, P.; Howard, R.; Kuzin, S.; Schmutz, W.; Tsinganos, K.; Turck-Chièze, S.; Zhukov, A. Bibcode: 2010cosp...38.1921D Altcode: 2010cosp.meet.1921D Classical externally-occulted coronagraphs are presently limited in their performances by the distance between the external occulter and the front objective. The diffraction fringe from the occulter and the vignetted pupil which degrades the spatial resolution prevent useful observa-tions of the white light corona inside typically 2-2.5 Rsun. Formation flying offers an elegant solution to these limitations and allows conceiving giant, externally-occulted coronagraphs us-ing a two-component space system with the external occulter on one spacecraft and the optical instrument on the other spacecraft at distances of hundred meters. Such an instrument has just been selected by ESA to fly (by the end of 2013) on its PROBA-3 mission, presently in phase B, to demonstrate formation flying. It will perform both high spatial resolution imaging of the solar corona as well as 2-dimensional spectroscopy of several emission lines (in partic-ular the forbidden line of FeXIV at 530.285 nm) from the coronal base out to 3 Rsun using a Fabry-Perot interferometer. The classical design of an externally-occulted coronagraph is adapted to the formation flying configuration allowing the detection of the very inner corona as close as 0.05 Rsun from the solar limb. By tuning the position of the occulter spacecraft, it may even be possible to try reaching the chromosphere and the upper part of the spicules. ASPIICS/PROBA-3 mission, payload and scientific objectives are presented. Title: First Performance of the GOLF-NG Instrumental Prototype Observing the Sun in Tenerife Authors: Salabert, D.; Turck-Chièze, S.; Barrière, J. C.; Carton, P. H.; Daniel-Thomas, P.; Delbart, A.; García, R. A.; Granelli, R.; Jiménez-Reyes, S. J.; Lahonde-Hamdoun, C.; Loiseau, D.; Mathur, S.; Nunio, F.; Pallé, P. L.; Piret, Y.; Robillot, J. M.; Simoniello, R. Bibcode: 2009ASPC..416..341S Altcode: 2008arXiv0810.3393S The primary challenge of Global Oscillations at Low Frequency New Generation (GOLF-NG) is the detection of the low-frequency solar gravity and acoustic modes, as well as the possibility to measure the high-frequency chromospheric modes. On June 8th 2008, the first sunlight observations with the multichannel resonant GOLF-NG prototype spectrometer were obtained at the Observatorio del Teide (Tenerife). The instrument performs integrated (Sun-as-a-star), Doppler velocity measurements, simultaneously at eight different heights in the D1 sodium line profile, corresponding to photospheric and chromospheric layers of the solar atmosphere. In order to study its performance, to validate the conceived strategy, and to estimate the necessary improvements, this prototype has been running on a daily basis over the whole summer of 2008 at the Observatorio del Teide. We present here the results of the first GOLF-NG observations, clearly showing the characteristics of the 5-minute oscillatory signal at different heights in the solar atmosphere. We compare these signals with simultaneous observations from Global Oscillations at Low Frequency (GOLF)/SoHO and from the Mark-I instrument—a node of the Birmingham Solar Oscillations Network (BiSON) network, operating at the same site. Title: What Can We Learn on the Structure and the Dynamics of the Solar Core with g Modes? Authors: Mathur, S.; Ballot, J.; Eff-Darwich, A.; García, R. A.; Jiménez-Reyes, S. J.; Korzennik, S. G.; Turck-Chièze, S. Bibcode: 2009ASPC..416..215M Altcode: 2008arXiv0810.2031M The detection of the signature of dipole gravity modes has opened the path to study the solar inner radiative zone. Indeed, g modes should be the best probes to infer the properties of the solar nuclear core that represents more than half of the total mass of the Sun. Concerning the dynamics of the solar core, we can study how future observations of individual g modes could enhance our knowledge of the rotation profile of the deep radiative zone. Applying inversions on a set of real p-mode splittings coupled with either one or several g modes, we have checked the improvement of the inferred rotation profile when different error bars are considered for the g modes. Moreover, using a new methodology based on the analysis of the almost constant separation of the dipole gravity modes, we can introduce new constraints on solar models. For that purpose, we can compare g-mode predictions computed from several models including different physical inputs with the g-mode asymptotic signature detected in Global Oscillations at Low Frequencies (GOLF) data and calculate the correlation. This work shows the great consistency between the signature of dipole gravity modes and our knowledge of p-modes: incompatibility of data with a present standard model including the Asplund composition. Title: Detecting individual gravity modes in the Sun Authors: Garcia, R. A.; Ballot, J.; Eff-Darwich, A.; Garrido, R.; Jimenez, A.; Mathis, S.; Moya, A.; Palle, P. L.; Regulo, C.; Salabert, D.; Suarez, J. C.; Turck-Chieze, S. Bibcode: 2009arXiv0911.5442G Altcode: Many questions are still open regarding the structure and the dynamics of the solar core. By constraining more this region in the solar evolution models, we can reduce the incertitudes on some physical processes and on momentum transport mechanisms. A first big step was made with the detection of the signature of the dipole-gravity modes in the Sun, giving a hint of a faster rotation rate inside the core. A deeper analysis of the GOLF/SoHO data unveils the presence of a pattern of peaks that could be interpreted as dipole gravity modes. In that case, those modes can be characterized, thus bringing better constraints on the rotation of the core as well as some structural parameters such as the density at these very deep layers of the Sun interior. Title: Impact of the physical processes in the modeling of HD 49933 Authors: Piau, L.; Turck-Chièze, S.; Duez, V.; Stein, R. F. Bibcode: 2009A&A...506..175P Altcode: 2009arXiv0907.4336P Context: On its asteroseismic side, the initial run of CoRoT was partly devoted to the solar like star HD 49933. The eigenmodes of this F dwarf have been observed with unprecedented accuracy.
Aims: We investigate quantitatively the impact of changes in the modeling parameters like mass and composition. More importantly we investigate how a sophisticated physics affects the seismological picture of HD 49933. We consider the effects of diffusion, rotation and the changes in convection efficiency.
Methods: We use the CESAM stellar evolution code coupled to the ADIPLS adiabatic pulsation package to build secular models and their associated oscillation frequencies. We also exploited the hydrodynamical code STAGGER to perform surface convection calculations. The seismic variables used in this work are: the large frequency separation, the derivative of the surface phase shift, and the eigenfrequencies νℓ=0,n=14 and νℓ=0,n=27.
Results: Mass and uncertainties on the composition have much larger impacts on the seismic variables we consider than the rotation. The derivative of the surface phase shift is a promising variable for the determination of the helium content. The seismological variables of HD 49933 are sensitive to the assumed solar composition and also to the presence of diffusion in the models. Title: On plasma radiative properties in stellar conditions Authors: Turck-Chièze, S.; Delahaye, F.; Gilles, D.; Loisel, G.; Piau, L. Bibcode: 2009HEDP....5..132T Altcode: 2012arXiv1201.4693T The knowledge of stellar evolution is evolving quickly thanks to an increased number of opportunities to scrutinize the stellar internal plasma properties by stellar seismology and by 1D and 3D simulations. These new tools help us to introduce the internal dynamical phenomena in stellar modeling. A proper inclusion of these processes supposes a real confidence in the microscopic physics used, partly checked by solar or stellar acoustic modes. In the present paper we first recall which fundamental physics has been recently verified by helioseismology. Then we recall that opacity is an important ingredient of the secular evolution of stars and we point out why it is necessary to measure absorption coefficients and degrees of ionization in the laboratory for some well identified astrophysical conditions. We examine two specific experimental conditions which are accessible to large laser facilities and are suitable to solve some interesting questions of the stellar community: are the solar internal radiative interactions properly estimated and what is the proper role of the opacity in the excitation of the non-radial modes in the envelop of the β Cepheids and the Be stars? At the end of the paper we point out the difficulties of the experimental approach that we need to overcome. Title: Impact of large-scale magnetic fields on stellar structure and evolution Authors: Duez, Vincent; Mathis, S.; Brun, A. S.; Turck-Chièze, S. Bibcode: 2009IAUS..259..177D Altcode: We study the impact on the stellar structure of a large-scale magnetic field in stellar radiation zones. The field is in magneto-hydrostatic (MHS) equilibrium and has a non force-free character, which allows us to study its influence both on the mechanical and and on the energetic balances. This approach is illustrated in the case of an Ap star where the magnetic field matches at the surface with an external potential one. Perturbations of the stellar structure are semi-analytically computed. The relative importance of the magnetic physical quantities is discussed and a hierarchy, aiming at distinguishing various refinement degrees in the implementation of a large-scale magnetic field in a stellar evolution code, is established. This treatment also allows us to deduce the gravitational multipolar moments and the change in effective temperature associated with the presence of a magnetic field. Title: DynaMICCS: The Sun as an Integrated Magnetic System Authors: Turck-Chièze, S.; Mathis, S. Bibcode: 2009EM&P..104...11T Altcode: 2008EM&P..tmp...36T After the observations of SoHO, there is a real need to pursue global solar observations from the core to the corona and to put new constraints on the dynamical processes which act inside and outside the Sun. The DynaMICCS mission proposed to ESA in the framework of COSMIC VISION 2015-2025 has this objective. We concentrate here on the motivations to look for the magnetism of the solar radiative zone. Title: Impact of a Large-Scale Magnetic Field on Stellar Structure Authors: Duez, V.; Mathis, S.; Brun, A. S.; Turck-Chièze, S. Bibcode: 2009AIPC.1121...55D Altcode: We present the derivation of non force-free magneto-hydrostatic (MHS) equilibria in spherical geometry, supposing any prescription for the toroidal current. This allows us to study the influence on the stellar structure of a large-scale magnetic field, both on the mechanical and on the energetical balances. Two cases illustrate this approach: (i) the field is buried below a given radius, in order to model deep fossil magnetic fields in solar-like stars; (ii) the internal field matches at the surface with an external potential magnetic field that corresponds to fossil fields in more massive stars. The stellar structure perturbations are semi-analytically computed in both cases. This allows us to establish a hierarchy between the orders of magnitude of the different terms. Finally, the limit of validity of the linear perturbation is discussed. Title: The DynaMICCS perspective. A mission for a complete and continuous view of the Sun dedicated to magnetism, space weather and space climate Authors: Turck-Chièze, S.; Lamy, P.; Carr, C.; Carton, P. H.; Chevalier, A.; Dandouras, I.; Defise, J. M.; Dewitte, S.; Dudok de Wit, T.; Halain, J. P.; Hasan, S.; Hochedez, J. F.; Horbury, T.; Levacher, P.; Meissonier, M.; Murphy, N.; Rochus, P.; Ruzmaikin, A.; Schmutz, W.; Thuillier, G.; Vivès, S. Bibcode: 2009ExA....23.1017T Altcode: 2008ExA...tmp...42T The DynaMICCS mission is designed to probe and understand the dynamics of crucial regions of the Sun that determine solar variability, including the previously unexplored inner core, the radiative/convective zone interface layers, the photosphere/chromosphere layers and the low corona. The mission delivers data and knowledge that no other known mission provides for understanding space weather and space climate and for advancing stellar physics (internal dynamics) and fundamental physics (neutrino properties, atomic physics, gravitational moments...). The science objectives are achieved using Doppler and magnetic measurements of the solar surface, helioseismic and coronographic measurements, solar irradiance at different wavelengths and in-situ measurements of plasma/energetic particles/magnetic fields. The DynaMICCS payload uses an original concept studied by Thalès Alenia Space in the framework of the CNES call for formation flying missions: an external occultation of the solar light is obtained by putting an occulter spacecraft 150 m (or more) in front of a second spacecraft. The occulter spacecraft, a LEO platform of the mini sat class, e.g. PROTEUS, type carries the helioseismic and irradiance instruments and the formation flying technologies. The latter spacecraft of the same type carries a visible and infrared coronagraph for a unique observation of the solar corona and instrumentation for the study of the solar wind and imagers. This mission must guarantee long (one 11-year solar cycle) and continuous observations (duty cycle > 94%) of signals that can be very weak (the gravity mode detection supposes the measurement of velocity smaller than 1 mm/s). This assumes no interruption in observation and very stable thermal conditions. The preferred orbit therefore is the L1 orbit, which fits these requirements very well and is also an attractive environment for the spacecraft due to its low radiation and low perturbation (solar pressure) environment. This mission is secured by instrumental R and D activities during the present and coming years. Some prototypes of different instruments are already built (GOLFNG, SDM) and the performances will be checked before launch on the ground or in space through planned missions of CNES and PROBA ESA missions (PICARD, LYRA, maybe ASPIICS). Title: The Dynamics perspective including the observation of the deep solar magnetism Authors: Turck-Chièze, S. Bibcode: 2009EAS....39...69T Altcode: The stellar internal magnetism is presently poorly known, even we have now some evidence that it plays a crucial role in different stages of stellar evolution. I first recall the helioseismic results coming from the SOHO mission on the deep interior. Then I show how we hope to observe directly or indirectly the deep solar magnetism by the simultaneous detection of gravity modes, acoustic modes and other phenomena. The two following sections compare the different techniques of observation and show the interest of a multichannel resonant spectrometer both for studying the deep dynamics of the core and for putting some constraints on the stellar atmospheric models. The last section describes the DynaMICCS mission submitted to ESA in the framework of Cosmic Vision 2015-2025 and the observations of the coming decade with the GOLF-NG instrument dedicated to the magnetism of the core and to the region located between photosphere and chromosphere. Title: Impact of a Radius and Composition Variation on Stratification of the Solar Subsurface Layers Authors: Lefebvre, S.; Nghiem, P. A. P.; Turck-Chièze, S. Bibcode: 2009ApJ...690.1272L Altcode: 2008arXiv0809.1726L Several works have reported changes of the Sun's subsurface stratification inferred from f-mode or p-mode observations. Recently, a nonhomologous variation of the subsurface layers with depth and time has been deduced from f-modes. Progress on this important transition zone between the solar interior and the external part supposes a good understanding of the interplay between the different processes which contribute to this variation. This paper is the first of a series where we aim to study these layers from the theoretical point of view. For this first paper, we use solar models obtained with the CESAM code, in its classical form, and analyze the properties of the computed theoretical f-modes. We examine how a pure variation in the calibrated radius influences the subsurface structure and we also show the impact of an additional change of composition on the same layers. Then we use an inversion procedure to quantify the corresponding f-mode variation and its capacity to infer the radius variation. We deduce an estimate of the amplitude of the 11 year cyclic photospheric radius variation. Title: The Rotation of the Solar Core Authors: Turck-Chièze, S. Bibcode: 2009LNP...765..123T Altcode: In order to get a unified representation of stars, one needs to introduce the internal dynamical processes in the stellar structure equations. The validation of these complex equations supposes a proper reproduction of the helioseismic observations. Indeed the helioseismic discipline can provide today a crucial insight into the solar internal rotation profile, thanks to acoustic modes and to the first gravity mode detections. This information largely improves the previous situation where only external stellar rotation rates or abundance anomalies were accessible. In this review, I summarize first the theoretical studies and our recent results; then I present the respective role of acoustic and gravity modes and I show the solar rotation profile deduced from the instruments onboard SoHO with its uncertainties. The confrontation of these results with the recent theoretical developments exhibits important differences which demonstrate that some complementary work is necessary on both observational and theoretical sides. Title: First asteroseismic results from CoRoT Authors: Michel, E.; Baglin, A.; Weiss, W. W.; Auvergne, M.; Catala, C.; Aerts, C.; Appourchaux, T.; Barban, C.; Baudin, F.; Briquet, M.; Carrier, F.; Degroote, P.; De Ridder, J.; Garcia, R. A.; Garrido, R.; Gutiérrez-Soto, J.; Kallinger, T.; Lefevre, L.; Neiner, C.; Poretti, E.; Samadi, R.; Sarro, L.; Alecian, G.; Andrade, L.; Ballot, J.; Benomar, O.; Berthomieu, G.; Boumier, P.; Charpinet, S.; de Batz, B.; Deheuvels, S.; Dupret, M. -A.; Emilio, M.; Fabregat, J.; Facanha, W.; Floquet, M.; Frémat, Y.; Fridlund, M.; Goupil, M. -J.; Grotsch-Noels, A.; Handler, G.; Huat, A. -L.; Hubert, A. -M.; Janot-Pacheco, E.; Kjeldsen, H.; Lebreton, Y.; Leroy, B.; Martayan, C.; Mathias, P.; Miglio, A.; Montalban, J.; Monteiro, M. J. P. F. G.; Mosser, B.; Provost, J; Regulo, C.; Renan de Medeiros, J.; Ribas, I.; Roca Cortés, T.; Roxburgh, I.; Suso, J.; Thoul, A.; Toutain, T.; Tiphene, D.; Turck-Chieze, S.; Vauclair, S.; Vauclair, G.; Zwintz, K. Bibcode: 2008CoAst.156...73M Altcode: About one year after the end of the first observational run and six months after the first CoRoT data delivery, we comment the data exploitation progress for different types of stars. We consider first results to illustrate how these data of unprecedented quality shed a new light on the field of stellar seismology. Title: Impact of Large-Scale Magnetic Fields on Stellar Structure and Prospectives on Stellar Evolution Authors: Duez, V.; Mathis, S.; Brun, A. -S.; Turck-Chièze, S. Bibcode: 2008sf2a.conf..459D Altcode: The influence of large-scale magnetic fields on stellar structure and stellar evolution is semi-analytically considered. The magnetic field is derived for a given axisymmetric azimuthal current, and is non force-free, acting thus directly on the stellar structure by modifying the hydrostatic balance. We discuss the relative importance of the various terms associated with the magnetic field in the mechanical and thermal balances before implementing its effects in a 1D stellar evolution code in a way that preserves its geometrical properties. Our purpose is illustrated by the case of an internal magnetic field matching at the surface of an Ap star with an external potential and multipolar magnetic field. Title: A Multisite Campaign to Measure Solar-like Oscillations in Procyon. I. Observations, Data Reduction, and Slow Variations Authors: Arentoft, Torben; Kjeldsen, Hans; Bedding, Timothy R.; Bazot, Michaël; Christensen-Dalsgaard, Jørgen; Dall, Thomas H.; Karoff, Christoffer; Carrier, Fabien; Eggenberger, Patrick; Sosnowska, Danuta; Wittenmyer, Robert A.; Endl, Michael; Metcalfe, Travis S.; Hekker, Saskia; Reffert, Sabine; Butler, R. Paul; Bruntt, Hans; Kiss, László L.; O'Toole, Simon J.; Kambe, Eiji; Ando, Hiroyasu; Izumiura, Hideyuki; Sato, Bun'ei; Hartmann, Michael; Hatzes, Artie; Bouchy, Francois; Mosser, Benoit; Appourchaux, Thierry; Barban, Caroline; Berthomieu, Gabrielle; Garcia, Rafael A.; Michel, Eric; Provost, Janine; Turck-Chièze, Sylvaine; Martić, Milena; Lebrun, Jean-Claude; Schmitt, Jerome; Bertaux, Jean-Loup; Bonanno, Alfio; Benatti, Serena; Claudi, Riccardo U.; Cosentino, Rosario; Leccia, Silvio; Frandsen, Søren; Brogaard, Karsten; Glowienka, Lars; Grundahl, Frank; Stempels, Eric Bibcode: 2008ApJ...687.1180A Altcode: 2008arXiv0807.3794A We have carried out a multisite campaign to measure oscillations in the F5 star Procyon A. We obtained high-precision velocity observations over more than three weeks with 11 telescopes, with almost continuous coverage for the central 10 days. This represents the most extensive campaign so far organized on any solar-type oscillator. We describe in detail the methods we used for processing and combining the data. These involved calculating weights for the velocity time series from the measurement uncertainties and adjusting them in order to minimize the noise level of the combined data. The time series of velocities for Procyon shows the clear signature of oscillations, with a plateau of excess power that is centered at 0.9 mHz and is broader than has been seen for other stars. The mean amplitude of the radial modes is 38.1 +/- 1.3 cm s-1 (2.0 times solar), which is consistent with previous detections from the ground and by the WIRE spacecraft, and also with the upper limit set by the MOST spacecraft. The variation of the amplitude during the observing campaign allows us to estimate the mode lifetime to be 1.5+ 1.9-0.8 days. We also find a slow variation in the radial velocity of Procyon, with good agreement between different telescopes. These variations are remarkably similar to those seen in the Sun, and we interpret them as being due to rotational modulation from active regions on the stellar surface. The variations appear to have a period of about 10 days, which presumably equals the stellar rotation period or, perhaps, half of it. The amount of power in these slow variations indicates that the fractional area of Procyon covered by active regions is slightly higher than for the Sun. Title: Variations of the solar granulation motions with height using the GOLF/SoHO experiment Authors: Lefebvre, S.; García, R. A.; Jiménez-Reyes, S. J.; Turck-Chièze, S.; Mathur, S. Bibcode: 2008A&A...490.1143L Altcode: 2008arXiv0808.0422L Context: Below 1 mHz, the power spectrum of helioseismic velocity measurements is dominated by the spectrum of convective motions (granulation and supergranulation) and it is difficult to detect the low-order acoustic modes and gravity modes.
Aims: We attempt to understand more clearly the behavior of solar granulation as a function of observing height in the solar atmosphere and with magnetic activity during solar cycle 23.
Methods: We analyze the Power Spectral Density (PSD) of eleven years of GOLF/SOHO velocity time series data using a Harvey-type model to characterize the properties of the convective motions in the solar oscillation power spectrum. We study the evolution of the granulation with both altitude in the solar atmosphere and solar activity.
Results: We first demonstrate that the traditional use of a Lorentzian profile to describe the envelope of the p modes is unsuitable for GOLF data. To model properly the solar spectrum, we must instead adopt a second Lorentzian profile. Secondly, we show that the granulation clearly evolves with height in the photosphere but does not present any significant variation with the activity cycle. Title: Impact of Large-Scale Magnetic Fields on Solar Structure Authors: Duez, V.; Mathis, S.; Brun, A. -S.; Turck-Chièze, S.; Le Poncin-Lafitte, C. Bibcode: 2008sf2a.conf..463D Altcode: We here focus on the impact of large-scale magnetic fields on the solar structure from its core up to its surface by treating semi-analytically the Magneto-HydroStatic (MHS) equilibria of a self-gravitating spherical shell. Then, the modifications of the internal structure of the Sun introduced by such a field are deduced, and the resulting multipolar gravitational moments are obtained. Title: Solar structure models Authors: Turck-Chièze, Sylvaine; Phi Nghiem, Phu Anh; Mathis, Stéphane Bibcode: 2008JPhCS.118a2030T Altcode: The Sun is a unique object in stellar evolution due to our unprecedent insight on its internal processes. We will illustrate in this review how the transition between a static vision to a more dynamical vision modifies the addressing questions on the solar radiative zone. Neutrinos and acoustic modes have first scrutinized the microscopic properties of the solar radiative plasma. Today, stimulated by the internal rotation profile determination, new questions emerge on the angular momentum transport by rotation, internal waves and on the role of magnetic fields to get access to the dynamical motions of this important region of the Sun. We will give some examples which demonstrate that the Sun is not yet under control. Title: Oscillations in Procyon A: First results from a multi-site campaign Authors: Hekker, S.; Arentoft, T.; Kjeldsen, H.; Bedding, T. R.; Christensen-Dalsgaard, J.; Reffert, S.; Bruntt, H.; Butler, R. P.; Kiss, L. L.; O'Toole, S. J.; Kambe, E.; Ando, H.; Izumiura, H.; Sato, B.; Hartmann, M.; Hatzes, A. P.; Appourchaux, T.; Barban, C.; Berthomieu, G.; Bouchy, F.; García, R. A.; Lebrun, J. -C.; Martić, M.; Michel, E.; Mosser, B.; Nghiem, P. A. P.; Provost, J.; Samadi, R.; Thévenin, F.; Turck-Chièze, S.; Bonanno, S. A.; Benatti, S.; Claudi, R. U.; Cosentino, R.; Leccia, S.; Frandsen, S.; Brogaard, K.; Grundahl, F.; Stempels, H. C.; Bazot, M.; Dall, T. H.; Karoff, C.; Carrier, F.; Eggenberger, P.; Sosnowska, D.; Wittenmyer, R. A.; Endl, M.; Metcalfe, T. S. Bibcode: 2008JPhCS.118a2059H Altcode: 2007arXiv0710.3772H Procyon A is a bright F5IV star in a binary system. Although the distance, mass and angular diameter of this star are all known with high precision, the exact evolutionary state is still unclear. Evolutionary tracks with different ages and different mass fractions of hydrogen in the core pass, within the errors, through the observed position of Procyon A in the Hertzsprung-Russell diagram. For more than15 years several different groups have studied the solar-like oscillations in Procyon A to determine its evolutionary state. Although several studies independently detected power excess in the periodogram, there is no agreement on the actual oscillation frequencies yet. This is probably due to either insufficient high-quality data (i.e., aliasing) or due to intrinsic properties of the star (i.e., short mode lifetimes). Now a spectroscopic multi-site campaign using 10 telescopes world-wide (minimizing aliasing effects) with a total time span of nearly 4 weeks (increase the frequency resolution) is performed to identify frequencies in this star and finally determine its properties and evolutionary state. Title: CoRoT Measures Solar-Like Oscillations and Granulation in Stars Hotter Than the Sun Authors: Michel, Eric; Baglin, Annie; Auvergne, Michel; Catala, Claude; Samadi, Reza; Baudin, Frédéric; Appourchaux, Thierry; Barban, Caroline; Weiss, Werner W.; Berthomieu, Gabrielle; Boumier, Patrick; Dupret, Marc-Antoine; Garcia, Rafael A.; Fridlund, Malcolm; Garrido, Rafael; Goupil, Marie-Jo; Kjeldsen, Hans; Lebreton, Yveline; Mosser, Benoît; Grotsch-Noels, Arlette; Janot-Pacheco, Eduardo; Provost, Janine; Roxburgh, Ian W.; Thoul, Anne; Toutain, Thierry; Tiphène, Didier; Turck-Chieze, Sylvaine; Vauclair, Sylvie D.; Vauclair, Gérard P.; Aerts, Conny; Alecian, Georges; Ballot, Jérôme; Charpinet, Stéphane; Hubert, Anne-Marie; Lignières, François; Mathias, Philippe; Monteiro, Mario J. P. F. G.; Neiner, Coralie; Poretti, Ennio; Renan de Medeiros, José; Ribas, Ignasi; Rieutord, Michel L.; Roca Cortés, Teodoro; Zwintz, Konstanze Bibcode: 2008Sci...322..558M Altcode: 2008arXiv0812.1267M Oscillations of the Sun have been used to understand its interior structure. The extension of similar studies to more distant stars has raised many difficulties despite the strong efforts of the international community over the past decades. The CoRoT (Convection Rotation and Planetary Transits) satellite, launched in December 2006, has now measured oscillations and the stellar granulation signature in three main sequence stars that are noticeably hotter than the sun. The oscillation amplitudes are about 1.5 times as large as those in the Sun; the stellar granulation is up to three times as high. The stellar amplitudes are about 25% below the theoretic values, providing a measurement of the nonadiabaticity of the process ruling the oscillations in the outer layers of the stars. Title: The GOLF-NG prototype and the solar European perspective for cosmic vision 2015-2025 Authors: Turck-Chièze, Sylvaine; Mathur, Savita; Ballot, Jérome; García, Rafael A.; Carton, Pierre-Henri; Barrière, Jean-Christophe; Daniel-Thomas, Philippe; Delbart, Alain; Desforges, Daniel; Granelli, Rémi; Nunio, Francois; Piret, Yves; Pallé, Pere L.; Jiménez, Antonio J.; Jiménez-Reyes, Sébastian J.; Simoniello, Rosaria; Dyna MICCS Team Bibcode: 2008JPhCS.118a2044T Altcode: The progress on the dynamics of the radiative zone by global Doppler velocity measurements aboard SoHO (GOLF+ MDI) and with ground networks (BiSON and GONG) opens a new perspective for solar and stellar physics. It is why we prepare a new generation of solar resonant spectrometer. The objectives of the GOLF-NG instrument and its present status are described. We have demonstrated this year that most of the technical challenges have been successfully faced and the next steps are mentioned. We then recall the scientific questions that might be solved with the next generation of instruments in construction in different european laboratories to reach a complete 3D vision of our star from the core to the corona. Two formation flying missions DynaMICCS and HIRISE have been proposed to ESA in the framework of the 2015-2025 Cosmic Vision perspective to contribute to solve these questions. A strategy of measurements must be found for the next decade. Title: AsteroFLAG — from the Sun to the stars Authors: Chaplin, W. J.; Appourchaux, T.; Arentoft, T.; Ballot, J.; Baudin, F.; Bazot, M.; Bedding, T. R.; Christensen-Dalsgaard, J.; Creevey, O. L.; Duez, V.; Elsworth, Y.; Fletcher, S. T.; García, R. A.; Gough, D. O.; Jiménez, A.; Jiménez-Reyes, S. J.; Houdek, G.; Kjeldsen, H.; Lazrek, M.; Leibacher, J. W.; Monteiro, M. J. P. F. G.; Neiner, C.; New, R.; Régulo, C.; Salabert, D.; Samadi, R.; Sekii, T.; Sousa, S. G.; Toutain, T.; Turck-Chièze, S. Bibcode: 2008JPhCS.118a2048C Altcode: We stand on the threshold of a critical expansion of asteroseismology of Sun-like stars, the study of stellar interiors by observation and analysis of their global acoustic modes of oscillation. The Sun-like oscillations give a very rich spectrum allowing the internal structure and dynamics to be probed down into the stellar cores to very high precision. Asteroseismic observations of many stars will allow multiple-point tests of crucial aspects of stellar evolution and dynamo theory. The aims of the asteroFLAG collaboration are to help the community to refine existing, and to develop new, methods for analysis of the asteroseismic data on the Sun-like oscillators. Title: The Rotation of the Solar Radiative zone Authors: Turck-Chieze, S. Bibcode: 2008IAUS..252..257T Altcode: Dynamical processes are progressively introduced in stellar evolution. In this framework, the Sun is a very specific case where both models and observations have been developed in parallel during the last decade in order to progress on our present insight of solar like stars. In this poster I show the recent progress done on both sides for the rotation of the radiative zone. The present knowledge of the solar rotation profile comes from the detection of acoustic and gravity modes with the instruments GOLF and MDI aboard SoHO. In parallel we study the sensitivity of the theoretical rotation profiles obtained with the CESAM code using different rotation history in the premainsequence. Title: Update on g-mode research Authors: García, R. A.; Jiménez, A.; Mathur, S.; Ballot, J.; Eff-Darwich, A.; Jiménez-Reyes, S. J.; Pallé, P. L.; Provost, J.; Turck-Chièze, S. Bibcode: 2008AN....329..476G Altcode: 2008arXiv0802.4296G Since the beginning of this century we have attended a blooming of the gravity-mode research thanks to the unprecedented quality of the data available, either from space with SoHO, or from the ground-based networks as BiSON or GONG. From the first upper limit of the gravity-mode amplitudes fixed at 10 mm/s at 200 μHz given by Appourchaux et al. (2000), on one hand, a peak was supposed to be a component of the ℓ = 1, n = 1 mixed mode (García et al. 2001a, 2001b; Gabriel et al. 2002) and, on the other hand, a couple of patterns - multiplets - were attributed to gravity modes (Turck-Chièze et al. 2004; Mathur et al. 2007). One of these patterns, found around 220 μHz, could be labeled as the ℓ = 2, n =-3 g mode, which is expected to be the one with the highest surface amplitude (Cox & Guzik 2004). Finally, in 2007, García et al. were able to measure the fingertips of the dipole gravity modes looking for their asymptotic properties. In the present paper we present an update of the recent developments on this subject with special attention to the 220 μHz region, the dipole asymptotic properties and the impact of the incoming g-mode observations on the knowledge of the solar structure and rotation profile. Title: Sensitivity of helioseismic gravity modes to the dynamics of the solar core Authors: Mathur, S.; Eff-Darwich, A.; García, R. A.; Turck-Chièze, S. Bibcode: 2008A&A...484..517M Altcode: 2008arXiv0803.3966M Context: The dynamics of the solar core cannot be properly constrained through the analysis of acoustic oscillation modes. Gravity modes (g modes) are necessary to understand the structure and dynamics of the deepest layers of the Sun. Through recent progress on the observation of these modes - both individually and collectively - new information is available to contribute to inferring the rotation profile inside the nuclear burning core.
Aims: We aim to see the sensitivity of gravity modes to the rotation of the solar core. We analyze the influence of adding the splitting of one and several g modes to the data sets used in helioseismic numerical inversions. We look for constraints on the uncertainties required in the observations to improve the derived core rotation profile.
Methods: We compute three artificial sets of splittings derived for three rotation profiles: a rigid profile taken as a reference; a step-like profile and a smoother profile with higher rates in the core. We compute inversions based on regularized least-squares methodology (RLS) for both artificial data with real error bars and real data. Several sets of data are used: first, we invert only acoustic modes (p modes), then we add one and several g modes to which different values of observational uncertainties (75 and 7.5 nHz) are attributed. For the real data, we include g-mode candidate, ℓ=2, n=-3 with several splittings and associated uncertainties.
Results: We show that the introduction of one g mode in artificial data improves the rate in the solar core and gives an idea of the tendency of the rotation profile. The addition of more g modes lends greater accuracy to the inversions and stabilizes them. The inversion of real data with the g-mode candidate gives a rotation profile that remains unchanged down to 0.2 R⊙, whatever value of splitting we attribute to the g mode. Title: Laboratory performances of the solar multichannel resonant scattering spectrometer prototype of the GOLF-New Generation instrument Authors: Turck-Chièze, S.; Carton, P. H.; Mathur, S.; Barrière, J. -C.; Daniel-Thomas, P.; Lahonde-Hamdoun, C.; Granelli, R.; Loiseau, D.; Nunio, F.; Piret, Y.; Robillot, J. M. Bibcode: 2008AN....329..521T Altcode: 2008arXiv0806.3521T This article quickly summarizes the performances and results of the GOLF/SoHO resonant spectrometer, thus justifying to go a step further. We then recall the characteristics of the multichannel resonant GOLF-NG spectrometer and present the first successful performances of the laboratory tests on the prototype and also the limitations of this first technological instrument. Scientific questions and an observation strategy are discussed. Title: Asteroseismology of Procyon with SOPHIE Authors: Mosser, B.; Bouchy, F.; Martić, M.; Appourchaux, T.; Barban, C.; Berthomieu, G.; Garcia, R. A.; Lebrun, J. C.; Michel, E.; Provost, J.; Thévenin, F.; Turck-Chièze, S. Bibcode: 2008A&A...478..197M Altcode: 2007arXiv0712.1368M Context: This paper reports a 9-night asteroseismic observation program conducted in January 2007 with the new spectrometer sophie at the OHP 193-cm telescope, on the F5 IV-V target Procyon A.
Aims: This first asteroseismic program with sophie was intended to test the performance of the instrument with a bright but demanding asteroseismic target and was part of a multisite network.
Methods: The sophie spectra have been reduced with the data reduction software provided by OHP. The Procyon asteroseismic data were then analyzed with statistical tools. The asymptotic analysis has been conducted considering possible curvature in the échelle diagram analysis.
Results: These observations have proven the efficient performance of sophie used as an asteroseismometer, and succeed in a clear detection of the large spacing. An échelle diagram based on the 54-μHz spacing shows clear ridges. Identification of the peaks exhibits large spacings varying from about 52 μHz to 56 μHz. Outside the frequency range [0.9, 1.0 mHz] where the identification is confused, the large spacing increases at a rate of about dΔν/dn ≃ 0.2 μHz. This may explain some of the different values of the large spacing obtained by previous observations.

Based on observations collected with the sophie échelle spectrometer mounted on the 1.93-m telescope at OHP, France (program 06B.PNPS.BOU); http://www.obs-hp.fr/www/guide/ sophie/sophie-eng.html Table of radial velocity measurements is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/478/197 Title: Influence of a global magnetic field on stellar structure Authors: Duez, V.; Brun, A. S.; Mathis, S.; Nghiem, P. A. P.; Turck-Chièze, S. Bibcode: 2008MmSAI..79..716D Altcode: The theoretical framework we have developed to take into account the influence of a global axisymmetric magnetic field on stellar structure and evolution is described. The prescribed field, possibly time-dependent, is expanded in the vectorial spherical harmonics basis. Hydrostatic equilibrium and energetic balance are consequently modified. Convection's efficiency and onset are also revised. Finally, our numerical strategy and the results one can expect from the implementation of those theoretical results are discussed. Title: The dynamics of the solar radiative zone Authors: Turck-Chièze, Sylvaine; Talon, Suzanne Bibcode: 2008AdSpR..41..855T Altcode: The picture of the solar radiative zone is evolving quickly. This review is separated in two parts. We first recall how the two powerful probes of the solar interior, namely the neutrinos and helioseismology have scrutinized the microscopic properties of the solar radiative plasma. Recent observations stimulate today complementary activities beyond the standard stellar model through theoretical modeling of angular momentum transport by rotation, internal waves or (and) by magnetic fields to get access to the dynamical motions of this important region of the Sun. So in the second part, we summarize the first impact of such processes on the radiative zone. Title: Meridional circulation in the radiation zones of rotating stars: Origins, behaviors and consequences on stellar evolution Authors: Mathis, S.; Decressin, T.; Palacios, A.; Eggenberger, P.; Siess, L.; Talon, S.; Charbonnel, C.; Turck-Chièze, S.; Zahn, J. -P. Bibcode: 2007AN....328.1062M Altcode: Stellar radiation zones are the seat of meridional currents. This circulation has a strong impact on the transport of angular momentum and the mixing of chemicals that modify the evolution of stars. First, we recall in details the dynamical processes that are taking place in differentially rotating stellar radiation zones and the assumptions which are adopted for their modelling in stellar evolution. Then, we present our new results of numerical simulations which allow us to follow in 2D the secular hydrodynamics of rotating stars, assuming that anisotropic turbulence enforces a shellular rotation law and taking into account the transport of angular momentum by internal gravity waves. The different behaviors of the meridional circulation in function of the type of stars which is studied are discussed with their physical origin and their consequences on the transport of angular momentum and of chemicals. Finally, we show how this work is leading to a dynamical vision of the evolution of rotating stars from their birth to their death. Title: Division XI / Wg: Particle Astrophysics Authors: Schlickeiser, Reinhard; Blandford, Roger D.; Brillet, Alain; Fujimoto, Masa-Katsu; Madau, Piero; Olinto, Angela V.; Salvati, Marco; Schutz, Bernard F.; Smith, Peter F.; Spiro, Michel; Stepanyan, Arnold A.; Totsuka, Yoji; Turck-Chieze, Sylvaine; Voelk, Heinrich J. Bibcode: 2007IAUTB..26..207S Altcode: The business meeting of the Division XI Working Group on Particle Astrophysics took place in the morning of 25 August 2006, and was attended by 14 participants. Title: Simulations of Turbulent Convection in Rotating Young Solarlike Stars: Differential Rotation and Meridional Circulation Authors: Ballot, Jérôme; Brun, Allan Sacha; Turck-Chièze, Sylvaine Bibcode: 2007ApJ...669.1190B Altcode: 2007arXiv0707.3943B We present the results of three-dimensional simulations of the deep convective envelope of a young (10 Myr) 1 Msolar star, obtained with the anelastic spherical harmonic code. Since young stars are known to be faster rotators than their main-sequence counterparts, we have systematically studied the impact of the stellar rotation speed, by considering stars spinning up to 5 times as fast as the Sun. The aim of these nonlinear models is to understand the complex interactions between convection and rotation. We discuss the influence of the turbulence level and of the rotation rate on the intensity and the topology of the mean flows. For all of the computed models, we find a solar-type superficial differential rotation, with an equatorial acceleration, and meridional circulation that exhibits a multicellular structure. Even if the differential rotation contrast ΔΩ decreases only marginally for high rotation rates, the meridional circulation intensity clearly weakens according to our simulations. We have also shown that, for Taylor numbers above a certain threshold (Ta>~109), the convection can develop a vacillating behavior. Since simulations with high turbulence levels and rotation rates exhibit strongly cylindrical internal rotation profiles, we have considered the influence of baroclinic effects at the base of the convective envelope of these young Suns to see whether such effects can modify the otherwise near-cylindrical profiles to produce more conical, solarlike profiles. Title: VizieR Online Data Catalog: Procyon (alpha CMi) radial velocities (Mosser+, 2008) Authors: Mosser, B.; Bouchy, F.; Martic, M.; Appourchaux, T.; Barban, C.; Berthomieu, G.; Garcia, R. A.; Lebrun, J. C.; Michel, E.; Provost, J.; Thevenin, F.; Turck-Chieze, S. Bibcode: 2007yCat..34780197M Altcode: Time series of the radial velocities of Procyon recorder with the echelle spectrometer SOPHIE at Observatoire de Haute Provence in January 2007.

(1 data file). Title: On the Characteristics of the Solar Gravity Mode Frequencies Authors: Mathur, S.; Turck-Chièze, S.; Couvidat, S.; García, R. A. Bibcode: 2007ApJ...668..594M Altcode: Gravity modes are the best probes for studying the dynamics of the solar radiative zone, and especially the nuclear core. This paper shows how specific physical processes influence the theoretical g-mode frequencies for the l=1 and l=2 modes over a large range of radial orders n from -46 to -1, corresponding to potential SOHO observations. To this end, we compute different solar models, and we calculate the corresponding theoretical g-mode frequencies. These frequencies are sensitive to the physical inputs of our solar models in the high-frequency range of the oscillation power spectrum. At low frequency, we demonstrate that the periodic spacing (ΔPl) between two g-modes with consecutive orders n and with the same angular degree l does not vary significantly from one model to the other. For all the models considered, including models based on recent solar chemical abundances, the value of the characteristic quantity P0, the fundamental period of the g-modes, is constant within a 1 minute range (between 34 and 35 minutes). This result is in sharp contrast to the situation before the launch of the SOHO spacecraft, when the dispersion for P0 was large (with values ranging from 29 to 60 minutes). Then, we estimate the sensitivity of the oscillation frequency splittings to the solar core rotation. Finally, we review some features of the g-mode observations obtained with the GOLF instrument and based on an almost complete solar cycle. Some of these help us constrain the excitation mechanisms of g-modes. Title: Dynamical processes in the subsurface layers of the Sun Authors: Lefebvre, S.; Nghiem, P.; Turck-Chièze, S. Bibcode: 2007sf2a.conf..586L Altcode: Recent results obtained by Lefebvre and Kosovichev (2005) using f-modes frequencies from SOHO/MDI, indicate a change in the stratification of the subsurface layers, more precisely a non-homogeneous variation of these layers with depth and time. To progress on this transition zone between the solar interior and the external part, we begin to analyse the problem from a theoretical point of view. Using the CESAM code, we show how a small variation in the radius implies a variation in the subsurface structure. We use the theoretical f-modes frequencies to examine the corresponding changes in the stratification. Furthermore, we discuss the related physics, very complex in this zone, and show the variations of the temperature gradients, the density and pressure scale heights caused by the change in radius. Title: Review of the GOLF/SOHO helioseismic results and Perspectives Authors: Turck-Chièze, S.; GOLF Team; GOLF-Ng Team; Dynamics Teams Bibcode: 2007sf2a.conf..623T Altcode: Helioseismic measurements aboard SoHO deliver new facts useful to improve our understanding of Sun and stars. After more than a decade of measurements aboard SoHO, we present the helioseismic results obtained with the GOLF instrument. If the first published papers of this community have mainly contrained the internal microphysics, these last 5 years have revealed an unprecedent insight on the impact of the solar cycle on the outer layers thanks to acoustic modes and on the radiative zone dynamics thanks to gravity mode studies. We will show why GOLF appears as an excellent instrument for this purpose and what we have learned from 10 years of observation aboard SoHO with this french-spanish resonant spectrometer. The progress done today by Doppler velocity measurements aboard SoHO (GOLF+ MDI) and by ground networks (BiSON and GONG) opens a totally new perspective for solar and stellar physics. So we then mention the questions that might be solved with the next generation of instruments already in construction in different european laboratories including GOLF-NG. They lead to two formation flying missions DynaMICCS and HIRISE proposed in the framework of the ESA Cosmic Vision perspective. An european strategy of measurements is suggested to maintain this discipline in the best conditions for the two next decades in order to get quantitative estimate of the effective role of the solar variabilities along time. Title: Tracking Solar Gravity Modes: The Dynamics of the Solar Core Authors: García, Rafael A.; Turck-Chièze, Sylvaine; Jiménez-Reyes, Sebastian J.; Ballot, Jérôme; Pallé, Pere L.; Eff-Darwich, Antonio; Mathur, Savita; Provost, Janine Bibcode: 2007Sci...316.1591G Altcode: Solar gravity modes have been actively sought because they directly probe the solar core (below 0.2 solar radius), but they have not been conclusively detected in the Sun because of their small surface amplitudes. Using data from the Global Oscillation at Low Frequency instrument, we detected a periodic structure in agreement with the period separation predicted by the theory for gravity dipole modes. When studied in relation to simulations including the best physics of the Sun determined through the acoustic modes, such a structure favors a faster rotation rate in the core than in the rest of the radiative zone. Title: Probing the internal solar magnetic field through g modes Authors: Rashba, T. I.; Semikoz, V. B.; Turck-Chièze, S.; Valle, J. W. F. Bibcode: 2007MNRAS.377..453R Altcode: 2006astro.ph.11728R; 2007MNRAS.tmp..249R The observation of g-mode candidates by the Solar and Heliospheric Observatory (SOHO) mission opens the possibility of probing the internal structure of the solar radiative zone (RZ) and the solar core more directly than possible via the use of the p-mode helioseismology data. We study the effect of rotation and RZ magnetic fields on g-mode frequencies. Using a self-consistent static magnetohydrodynamics magnetic field model, we show that a 1 per cent g-mode frequency shift with respect to the Solar Seismic Model (SSEM) prediction, currently hinted in the Global Oscillation at Low Frequencies (GOLF) data, can be obtained for magnetic fields as low as 300 kG, for current measured modes of radial order n = -20. On the other hand, we also argue that a similar shift for the case of the low-order g-mode candidate (l = 2, n = -3) frequencies cannot result from rotation effects nor from central magnetic fields, unless these exceed 8 MG. Title: Understanding the origin of the solar cyclic activity for an improved earth climate prediction Authors: Turck-Chièze, Sylvaine; Lambert, Pascal Bibcode: 2007AdSpR..40..907T Altcode: This review is dedicated to the processes which could explain the origin of the great extrema of the solar activity. We would like to reach a more suitable estimate and prediction of the temporal solar variability and its real impact on the Earth climatic models. The development of this new field is stimulated by the SoHO helioseismic measurements and by some recent solar modelling improvement which aims to describe the dynamical processes from the core to the surface. We first recall assumptions on the potential different solar variabilities. Then, we introduce stellar seismology and summarize the main SOHO results which are relevant for this field. Finally we mention the dynamical processes which are presently introduced in new solar models. We believe that the knowledge of two important elements: (1) the magnetic field interplay between the radiative zone and the convective zone and (2) the role of the gravity waves, would allow to understand the origin of the grand minima and maxima observed during the last millennium. Complementary observables like acoustic and gravity modes, radius and spectral irradiance from far UV to visible in parallel to the development of 1D-2D-3D simulations will improve this field. PICARD, SDO, DynaMICCS are key projects for a prediction of the next century variability. Some helioseismic indicators constitute the first necessary information to properly describe the Sun-Earth climatic connection. Title: Advances in Secular Magnetohydrodynamics of Stellar Interiors Dedicated to Asteroseismic Spatial Missions Authors: Mathis, S.; Eggenberger, P.; Decressin, T.; Palacios, A.; Siess, L.; Charbonnel, C.; Turck-Chièze, S.; Zahn, J. -P. Bibcode: 2007EAS....26...65M Altcode: 2007astro.ph..3117M With the first light of COROT, the preparation of KEPLER and the future helioseismology spatial projects such as GOLF-NG, a coherent picture of the evolution of rotating stars from their birth to their death is needed. We describe here the modelling of the macroscopic transport of angular momentum and matter in stellar interiors that we have undertaken to reach this goal. First, we recall in detail the dynamical processes that are driving these mechanisms in rotating stars and the theoretical advances we have achieved. Then, we present our new results of numerical simulations which allow us to follow in 2D the secular hydrodynamics of rotating stars, assuming that anisotropic turbulence enforces a shellular rotation law. Finally, we show how this work is leading to a dynamical vision of the Hertzsprung-Russel diagram with the support of asteroseismology and helioseismology, seismic observables giving constraints on the modelling of the internal transport and mixing processes. In conclusion, we present the different processes that should be studied in the near future to improve our description of stellar radiation zones. Title: The Seismology Programme of CoRoT Authors: Michel, E.; Baglin, A.; Auvergne, M.; Catala, C.; Aerts, C.; Alecian, G.; Amado, P.; Appourchaux, T.; Ausseloos, M.; Ballot, J.; Barban, C.; Baudin, F.; Berthomieu, G.; Boumier, P.; Bohm, T.; Briquet, M.; Charpinet, S.; Cunha, M. S.; De Cat, P.; Dupret, M. A.; Fabregat, J.; Floquet, M.; Fremat, Y.; Garrido, R.; Garcia, R. A.; Goupil, M. -J.; Handler, G.; Hubert, A. -M.; Janot-Pacheco, E.; Lambert, P.; Lebreton, Y.; Lignieres, F.; Lochard, J.; Martin-Ruiz, S.; Mathias, P.; Mazumdar, A.; Mittermayer, P.; Montalban, J.; Monteiro, M. J. P. F. G.; Morel, P.; Mosser, B.; Moya, A.; Neiner, C.; Nghiem, P.; Noels, A.; Oehlinger, J.; Poretti, E.; Provost, J.; Renan de Medeiros, J.; De Ridder, J.; Rieutord, M.; Roca-Cortes, T.; Roxburgh, I.; Samadi, R.; Scuflaire, R.; Suarez, J. C.; Theado, S.; Thoul, A.; Toutain, T.; Turck-Chieze, S.; Uytterhoeven, K.; Vauclair, G.; Vauclair, S.; Weiss, W. W.; Zwintz, K. Bibcode: 2006ESASP1306...39M Altcode: 2008arXiv0811.1080M We introduce the main lines and specificities of the CoRoT Seismology Core Programme. The development and consolidation of this programme has been made in the framework of the CoRoT Seismology Working Group. With a few illustrative examples, we show how CoRoT data will help to address various problems associated with present open questions of stellar structure and evolution. Title: The DynaMICS perspective Authors: Turck-Chièze, S.; Schmutz, W.; Thuillier, G.; Jefferies, S.; Pallé; Dewitt, S.; Ballot, J.; Berthomieu, G.; Bonanno, A.; Brun, A. S.; Christensen-Dalsgaard, J.; Corbard, T.; Couvidat, S.; Darwich, A. M.; Dintrans, B.; Domingo, V.; Finsterle, W.; Fossat, E.; Garcia, R. A.; Gelly, B.; Gough, D.; Guzik, J.; Jiménez, A. J.; Jiménez-Reyes, S.; Kosovichev, A.; Lambert, P.; Lefebvre, S.; Lopes, I.; Martic, M.; Mathis, S.; Mathur, S.; Nghiem, P. A. P.; Piau, L.; Provost, J.; Rieutord, M.; Robillot, J. M.; Rogers, T.; Roudier, T.; Roxburgh, I.; Rozelot, J. P.; Straka, C.; Talon, S.; Théado, S.; Thompson, M.; Vauclair, S.; Zahn, J. P. Bibcode: 2006ESASP.624E..24T Altcode: 2006soho...18E..24T No abstract at ADS Title: Sensitivity of the predicted frequencies of l = 1 gravity modes to known physical processes Authors: Mathur, S.; Turck-Chièze, S.; Couvidat, S.; Garcia, R. A. Bibcode: 2006ESASP.624E..95M Altcode: 2006soho...18E..95M No abstract at ADS Title: Comparison of the solar velocity spectrum from MDI and GOLF during cycle 23 Authors: Lefebvre, S.; García, R. A.; Jiménez-Reyes, S. J.; Turck-Chièze, S. Bibcode: 2006ESASP.624E..94L Altcode: 2006soho...18E..94L No abstract at ADS Title: Dynamical processes in the solar radiative interior Authors: Palacios, A.; Talon, S.; Turck-Chièze, S.; Charbonnel, C. Bibcode: 2006ESASP.624E..38P Altcode: 2006soho...18E..38P; 2006astro.ph..9381P Recent seismic observations coming from acoustic and gravity modes clearly show that the solar standard model has reached its limits and can no longer be used to interpret satisfactorily seismic observations. In this paper, we present a review of the non-standard processes that may be added to the solar models in order to improve our understanding of the helioseismic data. We also present some results obtained when applying ``non-standard'' stellar evolution to the modelling of the Sun. Title: Procyon-A and Bootis: observational frequencies analyzed by the local-wave formalism Authors: Nghiem, P. A. P.; Ballot, J.; García, R. A.; Lambert, P.; Turck-Chièze, S. Bibcode: 2006ESASP.624E.116N Altcode: 2006astro.ph..8652N; 2006soho...18E.116N In the present analysis of Procyon-A and Eta-Bootis, we use the local-wave formalism which, despite its lack of precision inherent to any semi-analytical method, uses directly the model profile without any modification when calculating the acoustic mode eigenfrequencies. These two solar-like stars present steep variations toward the center due to the convective core stratification, and toward the surface due to the very thin convective zone. Based on different boundary conditions, the frequencies obtained with this formalism are different from that of the classical numerical calculation. We point out that (1) the frequencies calculated with the local-wave formalism seem to agree better with observational ones. All the frequencies detected with a good confident level including those classified as 'noise' find an identification, (2) some frequencies can be clearly identified here as indications of the core limit. Title: Cyclic variability of the seismic solar radius from SOHO/MDI and related physics Authors: Lefebvre, S.; Kosovichev, A. G.; Nghiem, P.; Turck-Chièze, S.; Rozelot, J. P. Bibcode: 2006ESASP.624E...9L Altcode: 2006soho...18E...9L No abstract at ADS Title: Detection of periodic signatures in the solar power spectrum On the track of l=1 gravity modes Authors: García, R. A.; Turck-Chièze, S.; Jiménez-Reyes, S. J.; Ballot, J.; Pallé, P. L.; Eff-Darwich, A.; Mathur, S.; Provost, J. Bibcode: 2006ESASP.624E..23G Altcode: 2006astro.ph.11806G; 2006soho...18E..23G In the present work we show robust indications of the existence of g modes in the Sun using 10 years of GOLF data. The present analysis is based on the exploitation of the collective properties of the predicted low-frequency (25 to 140 microHz) g modes: their asymptotic nature, which implies a quasi equidistant separation of their periods for a given angular degree (l). The Power Spectrum (PS) of the Power Spectrum Density (PSD), reveals a significant structure indicating the presence of features (peaks) in the PSD with near equidistant periods corresponding to l=1 modes in the range n=-4 to n=-26. The study of its statistical significance of this feature was fully undertaken and complemented with Monte Carlo simulations. This structure has a confidence level better than 99.86% not to be due to pure noise. Furthermore, a detailed study of this structure suggests that the gravity modes have a much more complex structure than the one initially expected (line-widths, magnetic splittings...). Compared to the latest solar models, the obtained results tend to favor a solar core rotating significantly faster than the rest of the radiative zone. In the framework of the Phoebus group, we have also applied the same methodology to other helioseismology instruments on board SoHO and ground based networks. Title: Dynamical processes in stellar radiation zones: secular magnetohydrodynamics of rotating stars Authors: Mathis, S.; Decressin, T.; Palacios, A.; Siess, L.; Charbonnel, C.; Turck-Chièze, S.; Zahn, J. -P. Bibcode: 2006ESASP.624E..36M Altcode: 2006soho...18E..36M No abstract at ADS Title: The internal structure of the Sun inferred from g modes and low-frequency p modes Authors: Elsworth, Y. P.; Baudin, F.; Chaplin, W; Andersen, B; Appourchaux, T.; Boumier, P.; Broomhall, A. -M.; Corbard, T.; Finsterle, W.; Fröhlich, C.; Gabriel, A.; García, R. A.; Gough, D. O.; Grec, G.; Jiménez, A.; Kosovichev, A.; Provost, J.; Sekii, T.; Toutain, T.; Turck-Chièze, S. Bibcode: 2006ESASP.624E..22E Altcode: 2006soho...18E..22E The Phoebus group is an international collaboration of helioseismologists, its aim being to detect low-frequency solar g modes. Here, we report on recent work, including the development and application of new techniques based on the detection of coincidences in contemporaneous datasets and the asymptotic properties of the g-mode frequencies. The length of the time series available to the community is now more than ten years, and this has reduced significantly the upper detection limits on the g-mode amplitudes. Furthermore, low-degree p modes can now be detected clearly at frequencies below 1000 μHz. Title: On the possible existence of localised vacillating convection state in rapidly rotating young solar-like stars Authors: Ballot, J.; Brun, A. S.; Turck-Chièze, S. Bibcode: 2006ESASP.624E.108B Altcode: 2006soho...18E.108B No abstract at ADS Title: Dynamical processes in stellar radiation zones Authors: Mathis, S.; Decressin, T.; Palacios, A.; Siess, L.; Charbonnel, C.; Turck-Chièze, S.; Zahn, J. -P. Bibcode: 2006IAUJD..17E..18M Altcode: With the progress of asteroseismology, we need a coherent picture of the evolution of rotating stars from their birth to their death. We describe here the modelling of the macroscopic transport of matter and angular momentum in stellar interiors that we have undertaken to achieve this goal. First, we briefly recall the dynamical processes that are driving these mechanisms in rotating stars. Then, we present our new results of numerical simulations which allow us to follow in 2D the secular hydrodynamics of rotating stars, assuming that anisotropic turbulence enforces a cellular rotation law. We discuss the different processes such as MHD instabilities that should be studied in the next future to improve our description of dynamical processes in stellar radiation zones. Finally, we show how our new results are leading us to a dynamical vision of Hertzsprung-Russell diagram, in support of asteroseismology. Title: Knowledge of the solar core dynamics through g modes Authors: Garcia, R. A.; Turck-Chièze, S.; Jimenez-Reyes, S. J.; Ballot, J.; Pallé, P. L.; Eff-Darwich, A.; Mathur, S.; Provost, J. Bibcode: 2006IAUJD..17E...8G Altcode: Helioseismology is able to study the solar interior through the observation of the solar oscillation modes propagating inside the Sun. Pressure-driven modes (p modes) provide a very detailed picture of the external convective zone above 0.7 R[⊙]and the radiative zone down to ~0.2 R[⊙] where only a few of such modes penetrate so far. To study deeper layers, still containing more than 40% of the totals mass, another type of oscillations are needed: the gravity-driven modes (g modes). Since the early 19 80s, this type of mode has been looked for. Only very recently have we have found some structures that are compatible with some global properties of these modes in the GOLF/ SOHO data. In this contribution we will show these signals. By explaining them as the signature of the asymptotic properties of the ℓ = 1 g modes, we could start constraining the solar core dynamics. Title: The DynaMICS project Authors: Garcia, R.; Turck-Chièze, S. Bibcode: 2006IAUJD..17E..33G Altcode: The DynaMICS (Dynamics and Magnetism from the Internal core to the Chromosphere of the Sun) space project is devoted to the long term (decades or centuries) global properties of the Sun. Its main scientific objectives are the following: (1) to get a complete 3D rotating and magnetic picture of the Sun from the central core up to the chromosphere, (2) to deduce from it the different sources of dynamos and their interplay, (3) to build models and predictions of the great maxima and minima solar activities, (4) to produce outputs useful to quantify the different aspects of the solar contribution to the Earth's climate. We outline here the instruments: GOLFNG, SODISM, PREMOS, MOF that we are developing to reach this goal. They will detect from space solar acoustic and gravity modes together with radius and irradiance variations and will improve our knowledge on the transition region between photosphere and chromosphere. Understanding the magnetic field of the radiative zone is a new and crucial objective, as this ingredient must play a role in the long-term Sun-Earth relationship and also in the knowledge of stellar interiors. These instruments will observe the Sun from an orbit around the Lagrangian L[1] point for a decade to ensure continuity, stability and measurements of tiny variations. Title: Curvelet analysis of asteroseismic data. I. Method description and application to simulated sun-like stars Authors: Lambert, P.; Pires, S.; Ballot, J.; García, R. A.; Starck, J. -L.; Turck-Chièze, S. Bibcode: 2006A&A...454.1021L Altcode: 2006astro.ph..4092L Context: .The detection and identification of oscillation modes (in terms of their ℓ, m, and successive n) is a great challenge for present and future asteroseismic space missions. "Peak tagging" is an important step in the analysis of these data to provide estimations of stellar oscillation mode parameters, i.e., frequencies, rotation rates, and further studies on the stellar structure.
Aims: .Our goal is to increase the signal-to-noise ratio of the asteroseismic spectra computed from the time series that are representative of MOST and CoRoT observations (30- and 150-day observations).
Methods: .We apply the curvelet transform - a recent image processing technique that looks for curved patterns - to echelle diagrams built using asteroseismic power spectra. In the resulting diagram, the eigenfrequencies appear as smooth continuous ridges. To test the method, we use Monte-Carlo simulations of several sun-like stars with different combinations of rotation rates, rotation-axis inclination, and signal-to-noise ratios.
Results: .The filtered diagrams enhance the contrast between the ridges of the modes and the background, allowing a better tagging of the modes and a better extraction of some stellar parameters. Monte-Carlo simulations have also shown that the region where modes can be detected is enlarged at lower and higher frequencies compared to the raw spectra. In addition, the extraction of the mean rotational splitting from modes at low frequency can be done more easily using the filtered spectra rather than the raw spectra.
Title: Scientific Objectives of the Novel Formation Flying Mission Aspiics Authors: Turck-Chièze, S.; Schmutz, W.; Thuillier, G.; Jefferies, S.; Pallé; Dewitt, S.; Ballot, J.; Berthomieu, G.; Bonanno, A.; Brun, A. S.; Christensen-Dalsgaard, J.; Corbard, T.; Couvidat, S.; Darwich, A. M.; Dintrans, B.; Domingo, V.; Finsterle, W.; Fossat, E.; Garcia, R. A.; Gelly, B.; Gough, D.; Guzik, J.; Jiménez, A. J.; Jiménez-Reyes, S.; Kosovichev, A.; Lambert, P.; Lefebvre, S.; Lopes, I.; Martic, M.; Mathis, S.; Mathur, S.; Nghiem, P. A. P.; Piau, L.; Provost, J.; Rieutord, M.; Robillot, J. M.; Rogers, T.; Roudier, T.; Roxburgh, I.; Rozelot, J. P.; Straka, C.; Talon, S.; Théado, S.; Thompson, M.; Vauclair, S.; Zahn, J. P. Bibcode: 2006ESASP.617E.164L Altcode: 2006soho...17E.164L No abstract at ADS Title: The EUV Variability Experiment (EVE) on the Solar Dynamics Observatory (SDO): Science Plan and Instrument Overview Authors: Turck-Chièze, S.; Schmutz, W.; Thuillier, G.; Jefferies, S.; Pallé; Dewitt, S.; Ballot, J.; Berthomieu, G.; Bonanno, A.; Brun, A. S.; Christensen-Dalsgaard, J.; Corbard, T.; Couvidat, S.; Darwich, A. M.; Dintrans, B.; Domingo, V.; Finsterle, W.; Fossat, E.; Garcia, R. A.; Gelly, B.; Gough, D.; Guzik, J.; Jiménez, A. J.; Jiménez-Reyes, S.; Kosovichev, A.; Lambert, P.; Lefebvre, S.; Lopes, I.; Martic, M.; Mathis, S.; Mathur, S.; Nghiem, P. A. P.; Piau, L.; Provost, J.; Rieutord, M.; Robillot, J. M.; Rogers, T.; Roudier, T.; Roxburgh, I.; Rozelot, J. P.; Straka, C.; Talon, S.; Théado, S.; Thompson, M.; Vauclair, S.; Zahn, J. P. Bibcode: 2006ESASP.617E.165W Altcode: 2006soho...17E.165W No abstract at ADS Title: Detection of the Periodic Signatures of l=1 Solar g Modes with 10 Years of GOLF/SOHO Data Authors: Garcia, Rafael A.; Turck-Chiéze, Sylvaine; Jiménez-Reyes, Sebastián J.; Ballot, Jerome; Palle, Pere L.; Eff-Darwich, Antonio; Mathur, Savita; Provost, Janine Bibcode: 2006ESASP.617E...3G Altcode: 2006soho...17E...3G No abstract at ADS Title: Recent Progresses on g-Mode Search Authors: Appourchaux, T.; Andersen, B.; Baudin, F.; Boumier, P.; Broomhall, A. -M.; Chaplin, W.; Corbard, T.; Elsworth, Y.; Finsterle, W.; Fröhlich, C.; Gabriel, A.; Garcia, R.; Gough, D. O.; Grec, G.; Jiménez, A.; Kosovichev, A.; Provost, J.; Sekii, T.; Toutain, T.; Turck-Chièze, S. Bibcode: 2006ESASP.617E...2A Altcode: 2006soho...17E...2A No abstract at ADS Title: Dynamics of the Solar Radiative Zone: Present and Future Authors: Turck-Chièze, S. Bibcode: 2006ESASP.617E..39T Altcode: 2006soho...17E..39T No abstract at ADS Title: The Dynamics Project Authors: Turck-Chièze, S.; Schmutz, W.; Thuillier, G.; Jefferies, S.; Pallé; Dewitt, S.; Ballot, J.; Berthomieu, G.; Bonanno, A.; Brun, A. S.; Christensen-Dalsgaard, J.; Corbard, T.; Couvidat, S.; Darwich, A. M.; Dintrans, B.; Domingo, V.; Finsterle, W.; Fossat, E.; Garcia, R. A.; Gelly, B.; Gough, D.; Guzik, J.; Jiménez, A. J.; Jiménez-Reyes, S.; Kosovichev, A.; Lambert, P.; Lefebvre, S.; Lopes, I.; Martic, M.; Mathis, S.; Mathur, S.; Nghiem, P. A. P.; Piau, L.; Provost, J.; Rieutord, M.; Robillot, J. M.; Rogers, T.; Roudier, T.; Roxburgh, I.; Rozelot, J. P.; Straka, C.; Talon, S.; Théado, S.; Thompson, M.; Vauclair, S.; Zahn, J. P. Bibcode: 2006ESASP.617E.162T Altcode: 2006soho...17E.162T No abstract at ADS Title: Dynamical processes in stellar radiation zones: secular magnetohydrodynamics of rotating stars Authors: Mathis, S.; Decressin, T.; Palacios, A.; Siess, L.; Charbonnel, C.; Turck-Chièze, S.; Zahn, J. -P. Bibcode: 2006sf2a.conf..491M Altcode: With the imminent launch of COROT and the preparation of new helioseismology instruments such as GOLF-NG (cf. DynaMICS project), we need a coherent picture of the evolution of rotating stars from their birth to their death. We describe here the modeling of the macroscopic transport of angular momentum and matter in stellar interiors that we have undertaken to achieve this goal. First, we recall the dynamical processes that are driving this transport in rotating stars and the theoretical advances we have accomplished. Then, we present our new results of numerical simulations which allow us to follow in 2D the secular hydrodynamics of rotating stars, assuming that anisotropic turbulence enforces a shellular rotation law. Finally, we show how this work is leading to a dynamical vision of the Hertzsprung-Russel diagram in support of asteroseismology and helioseismology. Title: Solar gravity modes: Present and future Authors: Turck-Chièze, Sylvaine Bibcode: 2006AdSpR..37.1569T Altcode: 2005astro.ph.11126T Gravity modes are the best probes to study the solar radiative zone dynamics, especially in the nuclear core. These modes remain difficult to observe, but they are essential ingredients for progressing on the evolution of the Sun-Earth relationship at the level of centuries. Today, the knowledge of the internal dynamics comes from acoustic modes and concerns mainly the external 2% of the solar mass. Nevertheless, the flat rotation profile of the radiative zone compels physics beyond the standard framework. I summarize different attempts to look for gravity modes and the results obtained after 8 years of observation with the GOLF/SoHO instrument. Some gravity mode candidates (at 1 mm/s level) have appeared with more than 98% confidence level as quadruplets or quintuplets. These patterns, if confirmed as gravity modes, may reveal very exciting physics of the solar core. Getting information on rotation and magnetic field in the solar core are real keys to simulate a complete dynamical solar picture. The understanding of the solar dynamics, the precise energetic balance and its temporal evolution necessitate more observations of the radiative zone which constitutes 98% of the Sun by mass. Our expertise in Doppler velocity measurements allows a step further and a new instrumental concept to reach velocities as low as 0.1 mm/s. A prototype will join the Tenerife site in 2006 and a space version is proposed to CNES and ESA as a microsatellite or part of a payload at the L1 Lagrange point. Title: GOLF-NG spectrometer, a space prototype for studying the dynamics of the deep solar interior Authors: Turck-Chièze, Sylvaine; Carton, Pierre-Henri; Ballot, Jérome; Barrière, Jean-Christophe; Daniel-Thomas, Philippe; Delbart, Alain; Desforges, Daniel; Garcia, Rafaël A.; Granelli, Rémi; Mathur, Savita; Nunio, François; Piret, Yves; Pallé, Pere L.; Jiménez, Antonio J.; Jiménez-Reyes, Sebastian J.; Robillot, Jean Maurice; Fossat, Eric; Eff-Darwich, Antonio. M.; Gelly, Bernard Bibcode: 2006AdSpR..38.1812T Altcode: 2005astro.ph.10753T The GOLF-NG (Global Oscillations at Low Frequency New Generation) instrument is devoted to the search for solar gravity and acoustic modes, and also chromospheric modes from space. This instrument which is a successor to GOLF/SOHO will contribute to improve our knowledge of the dynamics of the solar radiative zone. It is a 15 points resonant scattering spectrometer, working on the D1 sodium line. A ground-based prototype is under construction to validate the difficult issues. It will be installed at the Teide Observatory, on Tenerife in 2006 to analyse the separation of the effects of the magnetic turbulence of the line from the solar oscillations. We are prepared to put a space version of this instrument including a capability of identification of the modes, in orbit during the next decade. This instrument should be included in the ILWS program as it offers a key to the improvement of our knowledge of the solar core in combination with observations from SDO and PICARD. We hope to determine the core rotation and magnetic field, through precise measurements of oscillation mode frequency splittings. Understanding the magnetic field of the radiative zone is important for progress in the study of solar activity sources, an important player for the long-term Sun-Earth relationship. Title: The origin of the solar cyclic activities: the DynaMICS project Authors: Turck-Chieze, S.; Brun, A. S.; Garcia, R. A.; Jiménez-Reyes, S. J.; Palle, P.; Dynamics Team Bibcode: 2006cosp...36.2001T Altcode: 2006cosp.meet.2001T In order to better estimate the earth climatic variations at scales corresponding to decennia or centuries it appears more and more important to understand the internal origin of the solar magnetic cyclic activities together with the evolution of the internal solar rotation profile It is the only way to be able to predict how they will evolve in the future The seismic techniques are totally adapted to this knowledge and an enriched information will allow to interpret the solar global variations as irradiance luminosity at different wavelengths and will measure temporal global mode characteristics which must be linked to the total magnetic fluxes ldots Our main objectives are to predict the characteristics of the coming solar cycles and to determine if there is different origins for the longer solar cycles or if it is only a temporal evolution of the eleven cycle 22 years which produces grand minima or maxima SDO is well adapted to progress on the convective zone with increased resolution in comparison with the SoHO mission it will allow to improve the 11 year solar cycle predictions In complementarity we consider very important to get a general description of the dynamics of the solar radiative zone which contains the main part of the solar mass and to understand the interconnection between magnetic fields of the radiative zone and of the convective zones Such information stays today poorly known even SoHO results on the solar radiative zone through acoustic and gravity modes are very promising to pursue this investigation In this Title: GOLF New Generation: a spectrophotometer for the quest of solar gravity modes Authors: Turck-Chièze, S.; Mathur, S.; Carton, P. H.; García, R. A.; Palle, P.; Ballot, J. Bibcode: 2005sf2a.conf..167T Altcode: The Global Oscillations at Low Frequency: New Generation instrument (GOLF-NG), the successor of GOLF aboard SoHO, is devoted to the study the dynamics of the solar radiative zone thanks to the detection of solar gravity modes and low-frequency acoustic modes. This instrument built under a French-Spanish collaboration, is based on the Doppler velocity method using a 15 points resonant scattering spectrometer working on the D1 sodium line and will be placed in Tenerife. The observations of the space version called DynaMICS (for Dynamics and Magnetism of the Innner Core of the Sun) will enable us to improve our knowledge of the radiative zone, especially the solar core and the influence of the Sun on our planet by the determination of the origin of the magnetic activities. The investigation of the sodium line will also provide interesting information on the atmosphere of the Sun, between the photosphere and the chromosphere. Title: The magnetism of the solar interior for a complete MHD solar vision Authors: Turck-Chièze, S.; Appourchaux, T.; Ballot, J.; et al. Bibcode: 2005ESASP.588..193T Altcode: 2005astro.ph.10854T; 2005tssc.conf..193T The solar magnetism is no more considered as a purely superficial phenomenon. The SoHO community has shown that the length of the solar cycle depends on the transition region between radiation and convection. Nevertheless, the internal solar (stellar) magnetism stays poorly known. Starting in 2008, the American instrument HMI/SDO and the European microsatellite PICARD will enrich our view of the Sun-Earth relationship. Thus obtaining a complete MHD solar picture is a clear objective for the next decades and it requires complementary observations of the dynamics of the radiative zone. For that ambitious goal, space prototypes are being developed to improve gravity mode detection. The Sun is unique to progress on the topology of deep internal magnetic fields and to understand the complex mechanisms which provoke photospheric and coronal magnetic changes and possible longer cycles important for human life. We propose the following roadmap in Europe to contribute to this "impressive" revolution in Astronomy and in our Sun-Earth relationship: SoHO (1995-2007), PICARD (2008-2010), DynaMICS (2009-2017) in parallel to SDO (2008-2017) then a world-class mission located at the L1 orbit or above the solar poles. Title: The life of stars and their planets Authors: Catala, C.; Aerts, C.; Aigrain, S.; Antonello, E.; Appourchaux, T.; Auvergne, M.; Baglin, A.; Barge, P.; Barstow, M. A.; Baudin, F.; Boumier, P.; Collier Cameron, A.; Christensen-Dalsgaard, J.; Cutispoto, G.; Deeg, H.; Deleuil, M.; Desidera, S.; Donati, J. -F.; Favata, F.; Foing, B. H.; Gameiro, J. F.; Garcia, R.; Garrido, F.; Horne, K.; Lanza, A. F.; Lanzafame, A. C.; Lecavelier Des Etangs, A.; Léger, A.; Mas-Hesse, M.; Messina, S.; Micela, G.; Michel, E.; Monteiro, M. J. P. F. G.; Mosser, B.; Noels, A.; Pagano, I.; Piotto, G.; Poretti, E.; Rauer, H.; Roca-Cortes, T.; Rodono, M.; Rouan, D.; Roxburgh, I.; Schneider, J.; Strassmeier, K.; Turck-Chièze, S.; Vauclair, S.; Vidal-Madjar, A.; Weiss, W. W.; Wheatley, P. Bibcode: 2005ESASP.588...99C Altcode: 2005tssc.conf...99C We lack a reliable scenario for the formation and evolution of stars and their planetary systems, involving key factors such as magnetic fields and turbulence. We present the case for a mission concept that will clarify these problems and give us a global view of the evolution of combined star and planetary systems. This will be achieved by simultaneously addressing the search for planetary transits in front of a large number of stars, including many nearby stars, the study of their internal structure and evolution via asteroseismology, and that of their magnetic activity, via UV monitoring. Title: Global solar Doppler velocity determination with the GOLF/SoHO instrument Authors: García, R. A.; Turck-Chièze, S.; Boumier, P.; Robillot, J. M.; Bertello, L.; Charra, J.; Dzitko, H.; Gabriel, A. H.; Jiménez-Reyes, S. J.; Pallé, P. L.; Renaud, C.; Roca Cortés, T.; Ulrich, R. K. Bibcode: 2005A&A...442..385G Altcode: The Global Oscillation at Low Frequencies (GOLF) experiment is a resonant scattering spectrophotometer on board the Solar and Heliospheric Observatory (SoHO) mission, originally designed to measure the disk-integrated solar oscillations of the Sun. This instrument was designed in a relative photometric mode involving both wings of the neutral sodium doublet (D1 at λ 5896 and D2 at λ 5890 Å). However, a "one-wing" photometric mode has been selected to ensure 100% continuity in the measurements after a problem in the polarization mechanisms. Thus the velocity is obtained from only two points on the same wing of the lines. This operating configuration imposes tighter constraints on the stability of the instrument with a higher sensitivity to instrumental variations. In this paper we discuss the evolution of the instrument during the last 8 years in space and the corrections applied to the measured counting rates due to known instrumental effects. We also describe a scaling procedure to obtain the variation of the Doppler velocity based on our knowledge of the sodium profile slope and we compare it to previous velocity estimations. Title: Solar models and solar neutrinos Authors: Turck-Chièze, S. Bibcode: 2005NuPhS.145...17T Altcode: I present the orientations of these last years to build a more complete picture of the Sun. This direction leads us to compare results from solar models (standard and not standard) to recent observations of the solar interior. We use the seismic results to build seismic models and deduce new neutrino predictions, including recent updated composition and nuclear reaction rates. Today, we get a coherent view of the Sun through the two totally independent approaches: helioseismology and neutrino detected fluxes. This is extremely promising for preparing the second step: to go beyond the standard framework of stellar evolution. So, I discuss also the perspectives for the next 5 years which will be crucial years and must lead to the discovery of new neutrino properties. Title: How does helioseismology constrain solar neutrino properties? Authors: Turck-Chièze, S. Bibcode: 2005NuPhS.143...35T Altcode: This review summarizes the advances in solar modelling due to helioseismic measurements. One objective is the correct determination of the different neutrino fluxes and the establishment of the first neutrino properties. The two solar probes (acoustic modes and detected neutrinos) are today in excellent agreement after introduction of the LMA solution for the neutrino oscillations. This consistency is impressive and confirms the interest to look to neutrinos of the Universe. We note that the introduction of recent improvements on essential ingredients of solar modelling put in evidence the limitation of the “Solar Standard Model”. Discrepancies between its results and solar observations are rich of physics beyond this framework, with evident perspectives to look for other neutrino properties, in pursuing the investigation of different objects of the Universe including the Sun. Title: Seismic constraints on open clusters Authors: Piau, L.; Ballot, J.; Turck-Chièze, S. Bibcode: 2005A&A...430..571P Altcode: 2005astro.ph..3157P The aim of this theoretical and modelling paper is to derive knowledge on the global and structural parameters of low-mass stars using asteroseismology and taking advantage of the stellar collective behavior within open clusters. We build stellar models and compute the seismic signal expected from main sequence objects in the 0.8-1.6 M⊙ range. We first evaluate apparent magnitudes and oscillations-induced luminosity fluctuations expected in the Hyades, the Pleiades and the α Persei clusters. The closest cluster presents a feasible challenge to observational asteroseismology in the present and near future. The remainder of the work therefore focuses on the Hyades. We combine seismological and classical computations to address three questions: what can be inferred about 1) mass; 2) composition; and 3) extension of outer convection zones of solar analogs in the Hyades. The first issue relies on the strong sensitivity of the large separation to mass. We show that seismic constraints provide masses to a precision level (0.05 M⊙) that is competitive with the actual mass estimations from binary systems. Then large separations (Δ ν) and second differences (δ2 ν) are used to respectively constrain metal and helium fractions in the Hyades. When plotted for several masses, the relation of effective temperature (Teff) vs. large separation (Δ ν) is found to be strongly dependent on the metal content. Besides this the second difference main modulation is related to the second ionization of helium. An accuracy in the helium mass fraction of 0.02 to 0.01 can be achieved provided mass and age are accurately known, which is the case for a few Hyades binary systems. The second difference modulations are also partly due to the discontinuity in stellar stratification at the convective envelope/radiative core transition. They permit direct insight in the stellar structure. We compute acoustic radii of the convective bases for different values of the mixing length theory parameter αMLT in convection modelling, i.e. different convective efficiency in the superadiabatic layers. For a given effective temperature we show that the acoustic radius changes with convection efficiency. This suggests that seismology can provide constraints on the extension of outer convection and also more generally on the direct approaches of convection and dynamical phenomena being currently developed. Title: MeV Neutrino Sources: The Sun and the Supernovae Authors: Turck-Chièze, Sylvaine Bibcode: 2005HiA....13....9T Altcode: No abstract at ADS Title: Quiet or Active Sun and the Neutrino Properties Authors: Turck-Chieze, S. Bibcode: 2005ppls.conf...45T Altcode: The Sun and the Supernovae are very interesting MeV neutrino sources and remarkable examples of symbiosis between astrophysics and particle physics researches. Thanks to helioseismology, we have now reached a clear characterization of the solar central plasma and consequently, we put strong constraints on the solar core temperature. We deduce a prediction of the most energetic neutrino fluxes with a high degree of confidence. Neutrino detections have also solved challenging questions, as the detection of the different flavors of neutrinos. The present impressive agreement between prediction of the seismic solar model and SNO detection leads to an unambiguous evidence for a solution of the neutrino puzzle and a clear demonstration of the presence of solar neutrino oscillations. It is now worth to notice that the main role of seismology is to build a dynamical view of the stellar interiors. The description of the magneto-hydrodynamical processes is nowadays the present objective for a renewal of the stellar discipline. This year, important results on the Sun constitute a real breakthrough towards a dynamical vision of the Sun from which we may hope to extract complementary solar neutrino properties. I comment here on the real interest to look for other neutrino properties with the solar source of neutrinos and give preliminary results. Title: Challenges in Stellar Models from Helioseismology to Asteroseismology Authors: Turck-Chièze, Sylvaine; Phi Nghiem, Phu Anh; Piau, Laurent Bibcode: 2005HiA....13..403T Altcode: Stellar evolution is improving very quickly thanks to precise observations and the introduction of hydrodynamical processes. These phenomena improve our vision of stars in the phases where they have a dominant role. I shall present some challenging problems choosen in young clusters high mass stars or final stages of evolution.

Helio and asteroseismology will largely contribute to validate our understanding of the dynamical aspects which are not totally undercontrolled with present computer performances.

The Sun is the crucial guide for developping tools useful for future space missions. I shall introduce the difficulties and highlights of this unique case when we look to the Sun as a star. This experience is extremely rich for the future asteroseismic observations. Some strategies of observation will be introduced to disentangle the validation of physical processes from the waiting asteroseismic observation difficulties. Title: Helioseismology, Neutrinos and Radiative Zones Authors: Turck-Chièze, S.; Couvidat, S.; Piau, L. Bibcode: 2005EAS....17..149T Altcode: 2005astro.ph.11008T The solar interior has been scrutinized by two different and independent probes during the last twenty years with important revisions of the solar model, including a recent heavy element abundance revision. Today, we get a quantitatively coherent picture (even incomplete) of the solar (stellar) radiative zones. In this review, we recall the clues for solar gravitational settling definitively established by the seismic determination of the photospheric helium content. We comment also on the need for mixing in the transition region between radiation and convection in the case of the Sun and of population II stars. We finally list the open questions and the importance to continue more precise investigations of the solar (stellar) radiative zone in detecting gravity modes with the project DynaMICS. Title: The solar radiative interior: gravity modes and future instrumentation Authors: Garcia, R. A.; Turck-Chieze, S.; Ballot, J.; Couvidat, S.; Eff-Darwich, A.; Jiménez-Reyes, S. J.; Mathur, S.; Pallé, P. L.; GOLF-Ng Team Bibcode: 2004sf2a.conf...99G Altcode: 2004sf2a.confE.281G Today, the knowledge of the solar radiative interior is obtained by the solar acoustic modes. Thanks to the latest modes detected by SoHO the sound speed has been determined down to 0.06 Ro with a resolution of 3%. This profile is used to improve the solar model and its deviations from a static vision. The rotation profile is now clearly established down to the limit of the core (Garcia et al. 2004). In order to progress toward the core and reduce the uncertainties in the radiative region, gravity modes should be measured. Recently, Turck-Chieze et al. (2004) have identified some patterns using GOLF data during the last solar minimum, that can be interpreted in terms of gravity modes. These candidates, with an amplitude of ~2 mm/s, are at the limit of the signal-to-noise ratio and are difficult to follow when the activity increases. Their research will continue until the end of the SoHO lifetime in 2008 during the next solar minimum. In the best case, only a few mixed and gravity modes will be detected with SoHO. This is the reason why a French-Spanish collaboration is now building a prototype of a new spatial instrument, GOLF-NG, that will be tested during the Summer 2005 in the Observatorio del Teide. GOLF-NG will directly address the problem of the solar convective background noise to improve the g-mode detection. Title: Astroseismology in open clusters Authors: Piau, Laurent; Ballot, Jerome; Turck-Chieze, Sylvaine Bibcode: 2004sf2a.conf..319P Altcode: 2004sf2a.confE.299P The surface oscillations of solar-like stars provide precious informations on their global characteristics (mass, composition) and structure. The open-clusters reveal particularly interesting in this respect. We have built stellar models of Hyades stars for different masses and plausible ages and compositions of this cluster. Several seismic quantities were subsequently evaluated. I will address the question of performances necessary to complete precise seismic observations for solar-like Hyades. Then I will present our prospective work in asteroseismology and I will show how the analysis of the collective seismic effects can improve our knowledge on these stars. For instance the relation between the acoustic radius of the inner radiative core and the effective temperature reveals extremely sensitive to the convective efficiency in the superadiabatic layers. This relation should allow to set constraints on convective efficiency and therefore on the hydrodynamical simulations of convection. Title: Turbulent Convection in Young Solar-like Stars: Influence of rotation Authors: Ballot, J.; Brun, A. S.; Turck-Chièze, S. Bibcode: 2004sf2a.conf..197B Altcode: 2004sf2a.confE.266B The study of the relationship between X-ray emission and rotation in young stars (Feigelson et al. 2003) and observations of magnetic-field topology of such stars with Zeeman-Doppler Imaging (Donati et al. 2003) indicate that the dynamo processes differ from those operating in main sequence stars. In this context, 3-D numerical simulations have been started. The first step is to study the purely hydrodynamic case. We have simulated the convective shell of a young sun (10 Myr) with the Anelastic Spherical Harmonic (ASH) code. We have studied the angular momentum transfer, the meridional circulation and the differential rotation in this shell. We have also studied the effects of different rotation rates (1, 2 and 5 solar rate). Title: Surprising Sun: A New Step Towards a Complete Picture? Authors: Turck-Chièze, S.; Couvidat, S.; Piau, L.; Ferguson, J.; Lambert, P.; Ballot, J.; García, R. A.; Nghiem, P. Bibcode: 2004PhRvL..93u1102T Altcode: 2004astro.ph..7176T Important revisions of the solar model ingredients have appeared recently. We first show that the updated CNO composition suppresses the anomalous position of the Sun in the known galactic enrichment. The following law, He/H=0.075+44.6 O/H in number fraction, is now compatible with all the indicators. We then suggest some directions of investigation to solve the discrepancies between the standard model and solar seismic observations. We finally update our predicted neutrino fluxes using a seismic model and all the recent progress. We get 5.31±0.6×106/cm2/s for the total 8B neutrinos, 66.5±4.4 SNU and 2.76±0.4 SNU for the gallium and chlorine detectors, all in remarkable agreement with the detected values including neutrino oscillations for the last two. So, the acoustic modes and detected neutrinos see the same Sun, but the standard model fails to reproduce them. Title: Global Magnetic Field Strength at Solar Surface: Mean Value and Variations with the Activity Cycle Authors: Nghiem, P. A. P.; García, R. A.; Turck-Chièze, S.; Jiménez-Reyes, S. J. Bibcode: 2004ESASP.559..577N Altcode: 2004soho...14..577N No abstract at ADS Title: Gravity Modes with a Resonant Scattering Spectrophotometer Authors: Turck-Chièze, S.; Garcia, R. A.; Couvidat, S.; Ballot, J.; Jiménez-Reyes, S. J.; Fossat, E.; Gelly, B.; Mathur, S.; Nghiem, P. A. P.; Pallé, P.; Robillot, Jm.; GOLF-Ng Technical Team Bibcode: 2004ESASP.559...85T Altcode: 2004soho...14...85T No abstract at ADS Title: Solar Low-Degree P-Mode Parameters after 8 Years of Velocity Measurements with SOHO Authors: García, R. A.; Jiménez-Reyes, S. J.; Turck-Chièze, S.; Ballot, J.; Henney, C. J. Bibcode: 2004ESASP.559..436G Altcode: 2004soho...14..436G No abstract at ADS Title: Helioseismology from the Blue and Red Wings of the NA Profile as Seen by GOLF Authors: García, R. A.; Jiménez-Reyes, S. J.; Turck-Chièze, S.; Mathur, S. Bibcode: 2004ESASP.559..432G Altcode: 2004soho...14..432G No abstract at ADS Title: Seismic extraction of the convective extent in solar-like stars. The observational point of view Authors: Ballot, J.; Turck-Chièze, S.; García, R. A. Bibcode: 2004A&A...423.1051B Altcode: Convection is the first manifestation of macroscopic motions in stars. In the next decade, the extent of the external convective zone of solar-like stars will have to be derived from the eigenfrequencies of their low-degree (ℓ=0,1 and 2) acoustic modes. In this paper, we compare different tracers of the base of the convective zone (BCZ) and show that the second difference δ2ν stays simple and well suited for analyzing real data. We suggest the use of \tilde{t}BCZ=(2<Δν>)-1 - \tilde{τ}BCZ as a quasi-non-biased indicator of the BCZ acoustic radius. The method is first checked on a long-time solar observation with GOLF, then on shorter real observations by VIRGO and 10 000 simulated observations of solar-like stars. We present results for different observational duration and stellar masses. The intrinsic error due to the method on the convective extent is smaller than 1.5% (in units of stellar acoustic radius) for stars with masses between 0.9 and 1.3 M⊙. The limited observational interval adds a supplementary uncertainty of about 1.6% for a 150-day long simulated observation. In this study, we have also analyzed the effects of stochastic excitation and of non-continuous runs of shorter lengths. We discuss how to take into account the variations in activity.

Appendix B is only available in electronic form at http://www.edpsciences.org Title: Erratum: ``Looking for Gravity-Mode Multiplets with the GOLF Experiment aboard SOHO'' (ApJ, 604, 455 [2004]) Authors: Turck-Chièze, S.; García, R. A.; Couvidat, S.; Ulrich, R. K.; Bertello, L.; Varadi, F.; Kosovichev, A. G.; Gabriel, A. H.; Berthomieu, G.; Brun, A. S.; Lopes, I.; Pallé, P.; Provost, J.; Robillot, J. M.; Roca Cortés, T. Bibcode: 2004ApJ...608..610T Altcode: As a result of an error at the Press, the second panel of Figure 9 was repeated twice in the top row of the printed, black-and-white version of this figure, and the first panel was omitted. This error appears in the print edition and the PDF and postscript (PS) versions available with the electronic edition of the journal, although the panels of the color figure displayed in the electronic article itself are correct. Please see below for the corrected print version of Figure 9. The Press sincerely regrets the error. Title: Dynamical Processes Induced by the Internal Solar Rotation Authors: Turck-Chièze, S. Bibcode: 2004IAUS..215..317T Altcode: No abstract at ADS Title: About the rotation of the solar radiative interior Authors: García, R. A.; Corbard, T.; Chaplin, W. J.; Couvidat, S.; Eff-Darwich, A.; Jiménez-Reyes, S. J.; Korzennik, S. G.; Ballot, J.; Boumier, P.; Fossat, E.; Henney, C. J.; Howe, R.; Lazrek, M.; Lochard, J.; Pallé, P. L.; Turck-Chièze, S. Bibcode: 2004SoPh..220..269G Altcode: In the modern era of helioseismology we have a wealth of high-quality data available, e.g., more than 6 years of data collected by the various instruments on board the SOHO mission, and an even more extensive ground-based set of observations covering a full solar cycle. Thanks to this effort a detailed picture of the internal rotation of the Sun has been constructed. In this paper we present some of the actions that should be done to improve our knowledge of the inner rotation profile discussed during the workshop organized at Saclay on June 2003 on this topic. In particular we will concentrate on the extraction of the rotational frequency splittings of low- and medium-degree modes and their influence on the rotation of deeper layers. Furthermore, for the first time a full set of individual |m|-component rotational splittings is computed for modes ℓ≤4 and 1<ν<2 mHz, opening new studies on the latitudinal dependence of the rotation rate in the radiative interior. It will also be shown that these splittings have the footprints of the differential rotation of the convective zone which can be extremely useful to study the differential rotation of other stars where only these low-degree modes will be available. Title: Looking for Gravity-Mode Multiplets with the GOLF Experiment aboard SOHO Authors: Turck-Chièze, S.; García, R. A.; Couvidat, S.; Ulrich, R. K.; Bertello, L.; Varadi, F.; Kosovichev, A. G.; Gabriel, A. H.; Berthomieu, G.; Brun, A. S.; Lopes, I.; Pallé, P.; Provost, J.; Robillot, J. M.; Roca Cortés, T. Bibcode: 2004ApJ...604..455T Altcode: This paper is focused on the search for low-amplitude solar gravity modes between 150 and 400 μHz, corresponding to low-degree, low-order modes. It presents results based on an original strategy that looks for multiplets instead of single peaks, taking into consideration our knowledge of the solar interior from acoustic modes. Five years of quasi-continuous measurements collected with the helioseismic GOLF experiment aboard the SOHO spacecraft are analyzed. We use different power spectrum estimators and calculate confidence levels for the most significant peaks. This approach allows us to look for signals with velocities down to 2 mm s-1, not far from the limit of existing instruments aboard SOHO, amplitudes that have never been investigated up to now. We apply the method to series of 1290 days, beginning in 1996 April, near the solar cycle minimum. An automatic detection algorithm lists those peaks and multiplets that have a probability of more than 90% of not being pure noise. The detected patterns are then followed in time, considering also series of 1768 and 2034 days, partly covering the solar cycle maximum. In the analyzed frequency range, the probability of detection of the multiplets does not increase with time as for very long lifetime modes. This is partly due to the observational conditions after 1998 October and the degradation of these observational conditions near the solar maximum, since these modes have a ``mixed'' character and probably behave as acoustic modes. Several structures retain our attention because of the presence of persistent peaks along the whole time span. These features may support the idea of an increase of the rotation in the inner core. There are good arguments for thinking that complementary observations up to the solar activity minimum in 2007 will be decisive for drawing conclusions on the presence or absence of gravity modes detected aboard the SOHO satellite. Title: Solar gravity modes: the present and future Authors: Turck-Chièze, S.; Garcià, R.; Fossat, E.; Gelly, B.; Palle, P.; Robillot, Jm; Golf-Ng Bibcode: 2004cosp...35.3949T Altcode: 2004cosp.meet.3949T Gravity modes are the best probes to study the solar radiative zone, in particular the nuclear core and to follow its potential variability with time and latitude. Nevertheless, their amplitude is small and the solar noise particularly high in the range of frequency where they stand (below 500 μ Hz). It is why they are looked for more than 20 years and actively serached with GOLF and MDI instruments aboard SoHO which offers the best conditions of observation. Some candidates (Turck-Chièze et al. 2004) have been identified in the GOLF instrument, during the period of low solar activity thanks to an original research of multiplets corresponding to surface amplitudes of about 2mm/s. The examination of the interesting frequency range (100 to 400 μ Hz) will be pursued up to the end of the SoHO mission scheduled for 2007. Today our knowledge of the radiative zone is due to acoustic modes. Recent clear progress is due to the detection of modes less influenced by the sun activity, in the range 400-1600 μ Hz. The sound speed is determined down to 0.06 Ro with a resolution of 3%. This profile is used to improve the solar model and its deviations from a static vision. The rotation profile is now clearly established down to the limit of the core and its rigidity can only be explained by invoking a magnetic field effect. We present here GOLF-NG (Turck-Chièze et al., 2000) built by a French Spanish collaboration to improve g-mode detection. Based on the Doppler velocity method using a resonant spectrometer with a 16 channels on the sodium line, the main objective of GOLF-NG is to contribute to get an MHD picture of the Sun to better understand the influence of the Sun on earth climate, in improving the detection by a factor 10 in decreasing the solar noise thanks to a variable magnet. Consequently, the physical information will be extracted at different heights in the atmosphere. A prototype will be installed in 2005 in Tenerife. Then a spatial version will be available for taking place in one project of the ILWS mission. Turck-Chièze, S., Robillot, J.M., Dzitko, H ., Boumier, P., Decaudin, M., Gabriel, A.H., Garcia, R.A., Grec, G., Pallé, P.L., Renaud, C., Schmidt, D., 2000, ESA SP-464, 331; Turck-Chieze, S., Garcia, R.A., Couvidat, S., et al., 2004, ApJ, vol 604, Title: The Sun as a reference for Eddington Authors: Turck-Chièze, S. Bibcode: 2004ESASP.538...95T Altcode: 2004sshp.conf...95T In this review, I point out the major achievements of the helioseismic community on the physical description of the solar interior and the related efforts which must be performed to reach a corresponding scientific return in asteroseismology with the Eddington mission. I comment on the characteristics of the low degree modes which are the only modes accessible to this mission. Using solar data obtained with the resonant spectrometer GOLF and with the photometric instrument VIRGO onboard SoHO, I recall the importance of the duration of the observations and of the mode characteristics for the determination of internal indicators. This work takes into account the role of stochastic excitation and of solar activity. From all these remarks, I deduce some points which should be discussed during the Eddington preparation phase, in order to guarantee good observations and to prepare for rapid interpretations after launch. Title: A possible method for detecting a convective core Authors: Nghiem, P. A. P.; Ballot, J.; Piau, L.; Turck-Chièze, S. Bibcode: 2004ESASP.538..377N Altcode: 2004sshp.conf..377N Intermediate mass stars feature a convective core which is often confined in less than 10% of their radius. That implies a sound speed discontinuity at the core edge, which is seen in the eigenfrequencies. But, because of the very deep location, the classical use of the second difference fails to detect it. We propose here to look directly at the large separation, for the modes whose internal turning points are around the discontinuity. This method is first tested with the Sun to detect the discontinuity. This method is first tested with the Sun to detect the discontinuity at the base of the convection zone, with degrees l = 20 to 50. Then it is applied to intermediate mass stars using low-degree modes l < 3 to explore the signature of a convective core. The example of α Centauri A is given. The evolution of the radiative core of young stars is also studied. Title: The solar neutrino puzzle Authors: Couvidat, S.; Turck-Chieze, S. Bibcode: 2004frun.conf..191C Altcode: No abstract at ADS Title: Solar gravity modes: the present and future Authors: Turck-Chièze, S.; Garcià, R.; Fossat, E.; Gelly, B.; Palle, P.; Robillot, Jm Bibcode: 2004cosp...35.3946T Altcode: 2004cosp.meet.3946T Gravity modes are the best probes to study the solar radiative zone, in particular the nuclear core and to follow its potential variability with time and latitude. Nevertheless, their amplitude is small and the solar noise particularly high in the range of frequency where they stand (below 500 μ Hz). It is why they are looked for more than 20 years and actively serached with GOLF and MDI instruments aboard SoHO which offers the best conditions of observation. Some candidates (Turck-Chièze et al. 2004) have been identified in the GOLF instrument, during the period of low solar activity thanks to an original research of multiplets corresponding to surface amplitudes of about 2mm/s. The examination of the interesting frequency range (100 to 400 μ Hz) will be pursued up to the end of the SoHO mission scheduled for 2007. Today our knowledge of the radiative zone is due to acoustic modes. Recent clear progress is due to the detection of modes less influenced by the sun activity, in the range 400-1600 μ Hz. The sound speed is determined down to 0.06 Ro with a resolution of 3%. This profile is used to improve the solar model and its deviations from a static vision. The rotation profile is now clearly established down to the limit of the core and its rigidity can only be explained by invoking a magnetic field effect. We present here GOLF-NG (Turck-Chièze et al., 2000) built by a French Spanish collaboration to improve g-mode detection. Based on the Doppler velocity method using a resonant spectrometer with a 16 channels on the sodium line, the main objective of GOLF-NG is to contribute to get an MHD picture of the Sun to better understand the influence of the Sun on earth climate, in improving the detection by a factor 10 in decreasing the solar noise thanks to a variable magnet. Consequently, the physical information will be extracted at different heights in the atmosphere. A prototype will be installed in 2005 in Tenerife. Then a spatial version will be available for taking place in one project of the ILWS mission. Turck-Chièze, S., Robillot, J.M., Dzitko, H ., Boumier, P., Decaudin, M., Gabriel, A.H., Garcia, R.A., Grec, G., Pallé, P.L., Renaud, C., Schmidt, D., 2000, ESA SP-464, 331; Turck-Chièze, S., Garcia, R.A., Couvidat, S., et al., 2004, ApJ, vol 604, Title: Extraction of the convective zone extension from solar-like stars Authors: Ballot, J.; García, R. A.; Turck-Chièze, S. Bibcode: 2004ESASP.538..265B Altcode: 2004sshp.conf..265B The aim of this study is to estimate the quality of the asteroseismic observations for 150 days of photometric measurements. We have used simulated data and VIRGO time series as a good example of a one-solar-mass Eddington target. From the extracted-mode frequencies we have tried to measure the position of the base of the convective zone (BCZ). We have studied the two following cases: in the first one, the observation is done during five consecutive months; in the second, we use five non-consecutive one-month observations. The effects of the stochastic excitation and the stellar activity on the frequency determination are studied and discussed. In this framework we are also developing a new semi-automatic algorithm to extract low-degree mode parameters without any a priori. Title: Solar Seismic Models and the Neutrino Predictions Authors: Couvidat, S.; Turck-Chièze, S.; Kosovichev, A. G. Bibcode: 2003ApJ...599.1434C Altcode: 2002astro.ph..3107C This paper focuses on the solar neutrino fluxes, the g-mode predictions, and the possible impact of the magnetic fields on the neutrino emission and transport. The Solar and Heliospheric Observatory (SOHO) spacecraft has allowed astrophysicists to achieve a major breakthrough in the knowledge of the solar core. Both GOLF and MDI instruments on SOHO have significantly improved the accuracy of the sound speed profile, mainly by the detection of low-degree low-order p-modes. Our study (Turck-Chièze and coworkers) has lead to precise neutrino predictions through constructing a seismic solar model that is in good agreement with the sound speed profile inferred by helioseismology in the radiative interior of the Sun. In this paper we present the details of this study and investigate new solar models validated by the acoustic modes. These new models are primarily used to derive the emitted neutrino fluxes. We show that these fluxes do not depend strongly on the modified physics as far as the model is consistent with the helioseismic observations in the core. We also show that an internal large-scale magnetic field cannot exceed a maximum strength of ~=3×107 G in the radiative zone and may increase the emitted 8B neutrino flux only by ~=2%. All the neutrino predictions here are compatible with the Sudbury Neutrino Observatory results, assuming three neutrino flavors. We deduce the electron and neutron radial densities that are needed to calculate the neutrino oscillation properties. Finally, we discuss how the magnetic fields may influence the neutrino transport through the RSFP process, for different values of Δm2. Title: The Rotation of the Deep Solar Layers Authors: Couvidat, S.; García, R. A.; Turck-Chièze, S.; Corbard, T.; Henney, C. J.; Jiménez-Reyes, S. Bibcode: 2003ApJ...597L..77C Altcode: 2003astro.ph..9806C From the analysis of low-order GOLF+MDI sectoral modes (l<=3, 6<=n<=15, |m|=l) and LOWL data (l>3), we derive the radial rotation profile by assuming no latitudinal dependence in the solar core. These low-order acoustic modes contain the most statistically significant information about the rotation of the deepest solar layers and should be least influenced by internal variability associated with the solar dynamo. After the correction of the sectoral splittings for their contamination by the rotation of the higher latitudes, we obtain a flat rotation profile down to 0.2 Rsolar. Title: Analysis of rotational frequency splittings sensitive to the rotation rate of the solar core Authors: García, R. A.; Eff-Darwich, A.; Korzennik, S. G.; Couvidat, S.; Henney, C. J.; Turck-Chièze, S. Bibcode: 2003ESASP.517..271G Altcode: 2003soho...12..271G Updated solar frequency splitting measurements suggest a slight decrease of the rotation rate below 0.25 Rsolar and, albeit preliminary, rule out a core rotating faster than the upper radiative zone. The estimates of the rotation rate of the deep solar layers are based on new rotational frequency splittings computed using data from the GOLF and MDI instruments on board SoHO. Such results, provided they are confirmed after further analysis, give additional insight into the dynamics of the solar core. Title: Solar Neutrino Predictions and Variability Authors: Turck-Chieze, Sylvaine Bibcode: 2003IAUJD...1E..23T Altcode: More and more precise measurements of solar neutrinos are now available which have pointed out the presence of oscillations between different flavours of neutrinos.

Nowadays thanks to helioseismology we get a better description of the solar interior which helps to describe the region of emission (central core) and the regions where the neutrino pass through. In this presentation I shall recall how we get now some predicted values on the neutrino emission in a classical framework. Then I shall comment on some constraints coming from the central dynamical effects which become available from recent seismic data. Finally I shall comment on the possible variability of the solar neutrino data and discuss the presence or absence of correlations between neutrino data and some solar signals. Title: The Search for the Solar Core Dynamics with SoHO/GOLF Authors: Couvidat, S.; Turck-Chieze, S.; Gracia, R. A.; Corbard, T. Bibcode: 2003ASPC..293..276C Altcode: 2003tdse.conf..276C We present the rotation profile we derive from the GOLF (plus LOWL) data. This profile shows the onset of a decrease in the rotation rate of the solar core. If confirmed, it will be useful to constrain some dynamic effects in the radiative interior and demonstrate the efficiency of angular momentum transport by gravity waves. We also present the search for gravity modes on the GOLF data. Detection of such oscillation modes will be a great breakthrough for the knowledge of the structure of the core, and the dynamic processes that occur in the deep layers. The search for both the rotation profile and gravity modes is strongly related to the dynamics of the core. Title: Challenging Problems in Helio and Asteroseismology Authors: Turck-Chieze, Sylvaine Bibcode: 2003IAUJD..12E..49T Altcode: Stellar evolution is improving very quickly thanks to precise observations and the introduction of hydrodynamical processes. These phenomena improve our vision of stars in the phases where they have a dominant role. I shall present some challenging problems choosen in young clusters high mass stars or final stages of evolution.

Helio and asteroseismology will largely contribute to validate our understanding of the dynamical aspects which are not totally undercontrolled with present computer performances.

The Sun is the crucial guide for developping tools useful for future space missions. I shall introduce the difficulties and highlights of this unique case when we look to the Sun as a star. This experience is extremely rich for the future asteroseismic observations. Some strategies of observation will be introduced to disentangle the validation of physical processes from the waiting asteroseismic observation difficulties. Title: Challenges in Stellar Models: from Helio to Asteroseismology Authors: Turck-Chieze, Sylvaine Bibcode: 2003IAUJD..12E..50T Altcode: Stellar evolution modelling is improving very quickly thanks to precise observations and the introduction of hydrodynamical processes. These phenomena improve our vision of stars in the phases in which they have a dominant role. I shall present some challenging problems chosen in young clusters high-mass stars or final stages of evolution.

Helio and asteroseismology will largely contribute to validate our understanding of the dynamical aspects which are not totally under control with present computer performances.

The Sun is the crucial guide for developing tools useful for future space missions. I shall introduce the difficulties and highlights of this unique case when we look to the Sun as a star. This experience is extremely rich for the future asteroseismic observations. Some strategies of observation will be introduced to disentangle the validation of physical processes from the expected asteroseismic observational difficulties. Title: What Can We Learn from Global Acoustic Modes about the Structure of the Sun and Centauri A? Authors: Ballot, J.; Turck-Chièze, S.; García, R. A.; Nghiem, P. A. P. Bibcode: 2003aahd.conf..497B Altcode: No abstract at ADS Title: A search for solar g modes in the GOLF data Authors: Gabriel, A. H.; Baudin, F.; Boumier, P.; García, R. A.; Turck-Chièze, S.; Appourchaux, T.; Bertello, L.; Berthomieu, G.; Charra, J.; Gough, D. O.; Pallé, P. L.; Provost, J.; Renaud, C.; Robillot, J. -M.; Roca Cortés, T.; Thiery, S.; Ulrich, R. K. Bibcode: 2002A&A...390.1119G Altcode: With over 5 years of GOLF data having some 90% continuity, a new attempt has been made to search for possible solar g modes. Statistical methods are used, based on the minimum of assumptions regarding the solar physics; namely that mode line-widths are small compared with the inverse of the observing time, and that modes are sought in the frequency interval 150 to 400 mu Hz. A number of simulations are carried out in order to understand the expected behaviour of a system consisting principally of a solar noise continuum overlaid with some weak sharp resonances. The method adopted is based on the FFT analysis of a time series with zero-padding by a factor of 5. One prominent resonance at 284.666 mu Hz coincides with a previous tentative assignment as one member of an n=1, l=1, p-mode multiplet. Components of two multiplets, previously tentatively identified as possible g-mode candidates from the GOLF data in 1998, continue to be found, although their statistical significance is shown to be insufficient, within the present assumption regarding the nature of the signal. An upper limit to the amplitude of any g mode present is calculated using two different statistical approaches, according to either the assumed absence (H0 hypothesis) or the assumed presence (H1 hypothesis) of a signal. The former yields a slightly lower limit of around 6 mm/s. Title: Global low frequency acoustic modes after half a solar cycle aboard SOHO: an improved view of the nuclear core Authors: Turck-Chièze, S.; Garcí, R. A.; Couvidat, S.; Kosovichev, A. G.; Bertello, L.; Corbad, T.; Berthomieu, G.; Provost, J.; Eff-Darwich, A. Bibcode: 2002ESASP.508..593T Altcode: 2002soho...11..593T Solar global oscillations have now been measured for more than 20 years. The study of these modes has contributed to improve, along time, the description of the solar core. We have now a proper access to this part of the Sun, with ground networks observing for more than 10 years and the three instruments aboard SOHO in a quasi continuous mode for now half a cycle. In this talk, we show the advantages of the global acoustic modes measured at low frequency. They are due to their longer lifetime and the reduced influence of the turbulent and variable surface effects. As a consequence, we have converged last year, after 30 years of unsuccess, to a boron-8 emitted neutrino flux in perfect agreement with the better understood detection of these neutrinos on earth. The splitting at low frequency is also now properly determined but the extracted rotation information is still limited in the core. It contains nevertheless the first dynamical vision of this part of the radiative zone. We will focus on it up to the end of the SOHO mission, together with the gravity mode region and the possible internal signature of the magnetic field. Some limits are given on these observables. Further improvements of their detectability are under study and will be mentioned. Title: The dynamics of the solar core with SoHO/GOLF Authors: Couvidat, S.; Turck-Chieze, S.; Garcia, R. A.; Corbard, T. Bibcode: 2002sf2a.conf..441C Altcode: We will present the latest results of the search for solar gravity modes and the solar core rotation with the GOLF instrument (aboard SoHO). The gravity modes are a primary target of the GOLF instrument. They are of great interest for the knowledge of the solar core and the physical phenomena that occur inside (pressure and density stratification, rotation profile, magnetic field, screening effect of the nuclear reactions...) We will describe the strategy developed at Saclay to detect them and the results we obtain. We find some candidates and put some constraints on their amplitude. Such amplitudes are important to better know the g-mode excitation mechanisms. We will also show the solar rotation profile for the solar interior (as deep as 0.2 R) derived with the latest SoHO data. The knowledge of this profile is needed to put some constraints on the angular momentum distribution and the related mechanisms. It is also needed to explain the oblateness of the Sun and have some information about a possible magnetic field in the core. The rotation rate derived favors a rigidly rotating radiative zone with a rate close to the one of the outer radiative zone, although we might have found some hints for a decrease of the rotation rate near the very center of the Sun. Title: Models of Metal-poor Stars with Gravitational Settling and Radiative Accelerations. I. Evolution and Abundance Anomalies Authors: Richard, O.; Michaud, G.; Richer, J.; Turcotte, S.; Turck-Chièze, S.; VandenBerg, Don A. Bibcode: 2002ApJ...568..979R Altcode: Evolutionary models have been calculated for Population II stars of 0.5-1.0 Msolar from the pre-main sequence to the lower part of the giant branch. Rosseland opacities and radiative accelerations were calculated taking into account the concentration variations of 28 chemical species, including all species contributing to Rosseland opacities in the OPAL tables. The effects of radiative accelerations, thermal diffusion, and gravitational settling are included. While models were calculated for both Z=0.00017 and 0.0017, we concentrate on models with Z=0.00017 in this paper. These are the first Population II models calculated taking radiative acceleration into account. It is shown that, at least in a 0.8 Msolar star, it is a better approximation not to let Fe diffuse than to calculate its gravitational settling without including the effects of grad(Fe). In the absence of any turbulence outside of convection zones, the effects of atomic diffusion are large mainly for stars more massive than 0.7 Msolar. Overabundances are expected in some stars with Teff>=6000 K. Most chemical species heavier than CNO are affected. At 12 Gyr, overabundance factors may reach 10 in some cases (e.g., for Al or Ni), while others are limited to 3 (e.g., for Fe). The calculated surface abundances are compared to recent observations of abundances in globular clusters as well as to observations of Li in halo stars. It is shown that, as in the case of Population I stars, additional turbulence appears to be present. Series of models with different assumptions about the strength of turbulence were then calculated. One series minimizes the spread on the Li plateau, while another was chosen with turbulence similar to that present in AmFm stars of Population I. Even when turbulence is adjusted to minimize the reduction of Li abundance, there remains a reduction by a factor of at least 1.6 from the original Li abundance. Independent of the degree of turbulence in the outer regions, gravitational settling of He in the central region reduces the lifetime of Population II stars by 4%-7% depending on the criterion used. The effect on the age of the oldest clusters is discussed in a forthcoming paper (Paper II). Just as in Population I stars where only a fraction of stars, such as AmFm stars, have abundance anomalies, one should look for the possibility of abundance anomalies of metals in some Population II turnoff stars but not necessarily in all. Expected abundance anomalies are calculated for 28 species and compared to observations of M92 as well as to Li observations in halo field stars. Title: Lithium Depletion in Pre-Main-Sequence Solar-like Stars Authors: Piau, L.; Turck-Chièze, S. Bibcode: 2002ApJ...566..419P Altcode: 2001astro.ph.11223P We examine the internal structure of solar-like stars in detail between 0.8 and 1.4 Msolar and during pre-main-sequence phase. Recent opacity computations of OPAL along with a new hydrodynamical mixing process have been considered. We also introduce up-to-date nuclear reaction rates and explore the impact of accretion, mixing length parameter, nonsolar distributions among metals, and realistic rotation history. Models predict lithium depletion that we compare to the 7Li content observations of the Sun and four young clusters of different metallicities and age. We show that we can distinguish two phases in lithium depletion: (1) a rapid nuclear destruction in the T Tauri phase before 20 Myr whatever the mass in our range and largely dependent on the extension and temperature of the convective zone, and (2) a second phase where the destruction is slow and moderate and which is largely dependent on the (magneto)hydrodynamic instability located at the base of the convective zone. Regarding composition we show the interest that takes on helium and above all the mixture of heavy elements: carbon, oxygen, silicium, and iron. We outline the importance of the O/Fe ratio. We note a reasonable agreement on lithium depletion for the two best-known cases, the Sun and the Hyades, for solar-like stars. Other clusters suggest that processes which may partly inhibit the predicted pre-main-sequence depletion cannot be excluded, in particular for stars below ~0.9 Msolar. We finally propose different research areas such as initial stellar models and more realistic atmospheres which could contribute to understanding better this early phase of evolution and which will be the object of subsequent works. Title: L-band x-ray absorption of radiatively heated nickel Authors: Chenais-Popovics, C.; Fajardo, M.; Gilleron, F.; Teubner, U.; Gauthier, J. -C.; Bauche-Arnoult, C.; Bachelier, A.; Bauche, J.; Blenski, T.; Thais, F.; Perrot, F.; Benuzzi, A.; Turck-Chièze, S.; Chièze, J. -P.; Dorchies, F.; Andiel, U.; Foelsner, W.; Eidmann, K. Bibcode: 2001PhRvE..65a6413C Altcode: 2002PhRvE..65a6413C Absorption of L-M and L-N transitions of nickel has been measured using point projection spectroscopy. The x-ray radiation from laser-irradiated gold cavities was used to heat volumetrically nickel foils ``tamped with carbon'' up to 20 eV. Experimental spectra have been analyzed with calculations based on the spin-orbit split arrays statistical approach and performed for each ionic species Ni5+ to Ni11+. Using a least-squares fit, this method provides an ion distribution broader than at local thermodynamic equilibrium, which is explained by spatial and temporal temperature gradients. A major improvement in the simulation of the absolute value of transmission is obtained with a resolved transition array statistical calculation that reproduces the experimental spectrum with the nominal areal mass density by taking into account the saturation of narrow lines. Title: Solar Neutrino Emission Deduced from a Seismic Model Authors: Turck-Chièze, S.; Couvidat, S.; Kosovichev, A. G.; Gabriel, A. H.; Berthomieu, G.; Brun, A. S.; Christensen-Dalsgaard, J.; García, R. A.; Gough, D. O.; Provost, J.; Roca-Cortes, T.; Roxburgh, I. W.; Ulrich, R. K. Bibcode: 2001ApJ...555L..69T Altcode: Three helioseismic instruments on the Solar and Heliospheric Observatory have observed the Sun almost continuously since early 1996. This has led to detailed study of the biases induced by the instruments that measure intensity or Doppler velocity variation. Photospheric turbulence hardly influences the tiny signature of conditions in the energy-generating core in the low-order modes, which are therefore very informative. We use sound-speed and density profiles inferred from GOLF and MDI data including these modes, together with recent improvements to stellar model computations, to build a spherically symmetric seismically adjusted model in agreement with the observations. The model is in hydrostatic and thermal balance and produces the present observed luminosity. In constructing the model, we adopt the best physics available, although we adjust some fundamental ingredients, well within the commonly estimated errors, such as the p-p reaction rate (+1%) and the heavy-element abundance (+3.5%); we also examine the sensitivity of the density profile to the nuclear reaction rates. Then, we deduce the corresponding emitted neutrino fluxes and consequently demonstrate that it is unlikely that the deficit of the neutrino fluxes measured on Earth can be explained by a spherically symmetric classical model without neutrino flavor transitions. Finally, we discuss the limitations of our results and future developments. Title: Low-Degree Low-Order Solar p Modes As Seen By GOLF On board SOHO Authors: García, R. A.; Régulo, C.; Turck-Chièze, S.; Bertello, L.; Kosovichev, A. G.; Brun, A. S.; Couvidat, S.; Henney, C. J.; Lazrek, M.; Ulrich, R. K.; Varadi, F. Bibcode: 2001SoPh..200..361G Altcode: Data recovered from the GOLF experiment on board the ESA/NASA SOHO spacecraft have been used to analyze the low-order low-degree solar velocity acoustic-mode spectrum below ν=1.5 mHz (i.e., 1≤n≤9,l≤2). Various techniques (periodogram, RLAvCS, homomorphic-deconvolution and RLSCSA) have been used and compared to avoid possible biases due to a given analysis method. In this work, the acoustic resonance modes sensitive to the solar central region are studied. Comparing results from the different analysis techniques, 10 modes below 1.5 mHz have been identified. Title: Solar Internal Composition and Nuclear Reaction Rates in the Light of Helioseismology Authors: Turck-chièze, S.; Nghiem, P.; Couvidat, S.; Turcotte, S. Bibcode: 2001SoPh..200..323T Altcode: Acoustic modes are a suitable probe to check the internal solar composition and give constraints on regions of turbulence or mixing in stellar interiors. The recent results obtained with the SOHO satellite involve practically all the acoustic modes and are extremely useful to check theoretical assumptions. If turbulence is favoured to explain lithium burning in the tachocline layers located at the base of the convection zone, central turbulent mixing seems to be strongly rejected by the present observations. Nuclear reaction rates cannot be directly verified by this type of probe but they are indirectly constrained through the behaviour of the sound speed. So, some puzzling problems concerning Maxwellian distribution or dynamical effects in stellar plasma are enlightened by the accuracy of the present seismic data. Title: The Seismology of Stars Authors: Turck-Chièze, Sylvaine Bibcode: 2001sf2a.conf..101T Altcode: Until recently, the great steps of stellar evolution have been studied only theoretically. This allowed to account for the observations of stellar surfaces. However many problems prove that the formalism is not complete: evolution of young stars, the problem of solar neutrinos, the burning of lithium, the origin of stellar winds, ultimate stages of stellar evolution... Often these open problems are linked to theoric limitations of the framework, which does not account for internal dynamics. Stellar seismology is a discipline which will contribute to change this situation while penetrating judiciously in the stellar interior. Thanks to the ground networks and SOHO satellite, the heliosismology has already revealed the internal dynamics of the Sun and has transformed this banal star into a true cosmic physics laboratory. The quality of the observations is also a formidable challenge for the theoricians who could validate their assumptions when the terrestrial laboratory remained impotent. I will show that confirming the complex physics included in the models is today an accomplished task, from the center of the Sun until its surface, with a precision of a few percent. But still more interesting, we begin to introduce the effects of rotation and of magnetic field, tackling today the dynamic processes which connect the stellar interior to the eruptive processes. This opens the gate to a three-dimensional representation of stars and to a better understanding of galactic enrichment or of the role of our star in our daily environment. However the Sun cannot, alone, account for the history of stellar angular momentum or of all stellar energetic phenomena. It is essential to extend this effort to a great number of samples, therefore I will show how this is possible and what we expect from asterosismology projects such as COROT or EDDINGTON. Title: Young solar-type stars evolution: the lithium depletion issue Authors: Piau, Laurent; Turck-Chièze, S. Bibcode: 2001sf2a.conf..139P Altcode: Asterosismology and light elements surface abundances allow direct insight of stellar structure. This talk presents the role of varying phenomena on the evolution of lithium surface abundance during solar-like pre-main sequence. Discrepancy between evolutionary models and young open cluters suggests that the development of the radiative core during this phase is badly understood. We discuss our results regarding the impact of microscopic phenomena related to opacities and therefore to metal fractions or macroscopic phenomena: accretion and rotation. Then we will address possible impact of protostellar collapse on present problem. Title: Recent Progress in Solar or Stellar Interior Modelling Authors: Turck-Chièze, S. Bibcode: 2001IAUS..203...29T Altcode: Acoustic modes are a suitable probe to check the internal solar composition and give constraints on regions of turbulence or mixing in stellar interiors. The satellite SOHO has measured the most significant acoustic modes including low degree low order modes which are less dependent on the solar surface effects. Consequently the resulting accuracy on the sound speed profile from the core to the surface has been largely improved along the four years of the SOHO mission. The recent results allow us to check theoretical assumptions of solar modelling. If turbulence is favoured to explain lithium burning in the tachocline layers located at the base of the convection zone, central mixing seems to be definitively rejected by the present observations. Nuclear reaction rates are also indirectly constrained through the behaviour of the sound speed. So, some puzzling problems on maxwellian distribution or dynamical effects in stellar plasma are enlightened by the accuracy of the present seismic data and the theoretical neutrino emissions partly checked. We begin to have nowadays a dynamical vision of the half external part of the Sun, thanks to the adding density and rotation profile. Gravity modes will be extremely useful to improve the spatial resolution in the radiative region. Title: g-mode: a new generation of helioseismic instrument Authors: Turck-Chièze, S.; Robillot, J. M.; Dzitko, H.; Boumier, P.; Decaudin, M.; Gabriel, A.; Garcia, R. A.; Gree, G.; Pallé, P. L.; Renaud, C.; Schmitt, D. Bibcode: 2001ESASP.464..331T Altcode: 2001soho...10..331T The GOLF team pushes a new concept of instrument devoted to the search of gravity modes and low order low frequency p modes in order to improve our knowledge of the deep solar interior. The instrumental concept is to measure the Doppler shift together with the time evolution of the D1 sodium line using a 15 point resonance spectrometer. A sodium vapor resonance cell placed in a static magnetic field varying along the longitudinal axis is used to sample simultaneously 8 points on each wing of the line. New Active Pixel Sensor detectors will be specifically designed for this instrument. A low spatial resolution of the Sun is also under study in this concept. First ground-based observations with this instrument are scheduled for 2001/2002 at Tenerife. The space concept of this instrument is under study in France as an R&T (Research and Technology) study sponsored by CNES, the French Space Agency. After some determining validation tests, this kind of instrument might be placed onboard either a micro satellite or a satellite dedicated to the study of the Sun. Title: Review of solar models and helioseismology Authors: Turck-Chièze, S. Bibcode: 2001NuPhS..91...73T Altcode: Acoustic modes are a suitable probe to determine the solar interior properties and give constraints on regions of turbulence or mixing. The recent results obtained with the SoHO satellite involve practically all the acoustic modes and are extremely useful to check theoretical assumptions. If turbulence is favoured to explain lithium burning in the tachocline layers located at the base of the convection zone, central turbulent mixing seems to be strongly rejected by the present observations. Nuclear reaction rates are indirectly constrained through the behaviour of the sound speed. So, some puzzling problems on maxwellian distribution or dynamical effects in stellar plasma are enlightened by the accuracy of the present seismic data. We begin to predict neutrino emission fluxes from helioseismology, and propose to use the difference between these emitted neutrino fluxes and neutrino fluxes detected on earth to deduce νe properties. Title: Lithium burning in the early stages of stellar evolution Authors: Piau, L.; Turck-Chièze, S. Bibcode: 2001ESASP.464..435P Altcode: 2001soho...10..435P Helioseismology has probably pointed out the important role of an hydrodynamical instability located just below the convective zone in the destruction of the solar lithium during the main sequence. This rotationally induced instability occurs in tachocline region where differential rotation disappears. In order to have a more complete and quantitative view of the general process of lithium destruction, we examine in the present study the way the lithium could be burned in the premainsequence phase for the Sun and young clusters' sunlike-stars. We discuss here the influence of different physical processes and present a scenario of the different stages of destruction. Title: Impact of Rotation and Magnetic Fields on Internal Stellar Composition Authors: Turck-Chièze, S. Bibcode: 2001coev.conf..145T Altcode: For decades, the post BBNS history of the elements in different media has been studied mainly theoretically. Here, we focus on the helioseismic SOHO satellite results. The precision of the used methods allows nowadays a direct insight of the solar interior, revealing the internal composition with a remarkable accuracy. Therefore, the role of the rotation and magnetic field begins to be studied and unsolved problems as lithium destruction and neutrino puzzle progress consequently. This method will be extended to other stars for progressing on dynamical processes of stellar evolution which contribute to the enrichment of the interstellar medium. Title: Lithium Burning in the Early Evolution of the Sun and Sun-like Stars Authors: Piau, L.; Turck-Chièze, S. Bibcode: 2001ASPC..243..639P Altcode: 2001fdtl.conf..639P No abstract at ADS Title: The search for solar low frequency resonant modes Authors: Bertello, L.; García, R. A.; Varadi, F.; Turck-Chièze, S.; Ulrich, R. K.; Henney, C. J.; Couvidat, S. Bibcode: 2001ESASP.464..479B Altcode: 2001soho...10..479B We present the results obtained from the analysis of 4-year long GOLF and MDI time series. The GOLF time series includes the period where the instrument operated in the blue wing of the doublet Na D lines, and also the data from the current red-wing photometric mode. Disk-averaged MDI velocity signals from the calibrated level-1.4 MDI LOI-proxy Doppler images were obtained using integrated spatially weighted masks. The analysis was carried out by Random-Lag Singular Cross-Spectrum Analysis. This technique searches for simultaneous oscillatory components in two or more time series, and has been proven to be very effective for the identification of solar acoustic modes of low angular degree and low radial order. In the present work we have extended our analysis to the frequency range between 200 and 1500 microHZ, which includes the region of low radial order gravity modes. Selected cases are presented and compared with the results obtained using classical spectral estimations based on Fourier transforms. Title: The physics of the solar core deduced from GOLF and MDI acoustic modes Authors: Turck-Chièze, S.; Kosovichev, A. G.; Couvidat, S.; García, R. A.; Nghiem, P.; Pérez Hernández, F.; Turcotte, S. Bibcode: 2001ESASP.464..485T Altcode: 2001soho...10..485T We use the recent results on solar acoustic modes coming from GOLF and MDI, to demonstrate that we improve the quality of the inversion of the sound speed and the density by avoiding several biases coming from the turbulent surface. The present accuracy allows a quantitative discussion on the physics of the solar nuclear core. We now exclude several phenomena which are incompatible with the present observations: central turbulent mixing or large modification of the pp chain nuclear reaction rates. We propose a solution to the difference between the Sun and solar models only in terms of turbulence at the base of the convective zone, an increase of the weak interaction p-p reaction rate by 2% in the framework of intermediate Mitler screening, and an underestimate of CNO composition of no more than 3%. Even if this solution is probably not unique, it allows a prediction of neutrino fluxes induced by helioseismology. We also note that nowadays, helioseismology puts just a few constraints on the reaction rates of the CNO cycle, and let place for lower high energy neutrino predictions. Title: Analysis of low frequency signal with the GOLF experiment: methodology and results Authors: García, R. A.; Bertello, L.; Turck-Chièze, S.; Couvidat, S.; Gabriel, A. H.; Henney, C. J.; Régulo, C.; Robillot, J. M.; Roca Cortés, T.; Ulrich, R. K.; Varadi, F. Bibcode: 2001ESASP.464..473G Altcode: 2001soho...10..473G Four years of GOLF velocity time series have been used to study the low frequency part of the solar spectrum below 1.5 mHz. This paper discusses the methods already developed for the research of the low-degree low-order acoustic modes by Garcia et al. (2000) and for the gravity modes by Turck-Chieze et al. (2000). These methods are based on our knowledge of the general theoretical properties of the p and g modes that lead us to determine the statistical significance of the structures (multiplets) present in the GOLF spectrum in terms of p- and g-mode candidates. In addition to the search of single peaks, we try to detect multiplets (l = 1, 2 and 3) which allows us to lower the detection threshold while keeping the same confidence level. We will concentrate the discussion on the limits of this search that only takes into account those peaks above a selected statistical threshold giving an estimation of the possible uncertainties due to the solar noise and the nature of the solar resonances. Title: Sensitivity of the GOLF signal to combined solar velocity and intensity variations Authors: Ulrich, R. K.; García, R. A.; Robillot, J. -M.; Turck-Chièze, S.; Bertello, L.; Charra, J.; Dzitko, H.; Gabriel, A. H.; Roca Cortés, T. Bibcode: 2000A&A...364..799U Altcode: The GOLF instrument provides a stable and continuous measurement of the intensity of spatially integrated sunlight in one wing of the sodium D lines. Because the detected radiation results from atomic scattering, the GOLF signal can be traced to an atomic reference wavelength. The planned operations were to involve a form of relative photometry through the use of measurements on both the blue and red wings of the solar D lines of neutral sodium. However, due to the occasional malfunction of the polarization subsystem a ``one wing photometric mode" operational alternative has been selected in order to ensure achievement of a 100% duty cycle. In this case, the signal observed consists of two photometric measurements at only one wing of each line of the sodium doublet separated by gx0.43 picometers (pm). The sodium cell system in GOLF combines photons scattered at three different wavelengths: one at D_1 and two at D_2. This paper developes a formalism to describe this system in terms of the solar spectral line profiles. A method of converting the one wing data to an effective velocity scale is presented. The method is applied to the nearly continuous 804 day sequence received from the GOLF instrument prior to the loss of telecommunications with SOHO on 24-June-1998. The resulting time sequence is part of the GOLF archive and can be made available to investigators. This publication describes some properties of this time series. Title: Solar Interior: Standard Models Authors: Turck-Chièze, S. Bibcode: 2000eaa..bookE2020T Altcode: Due to its proximity, there are many properties of the Sun which we can observe. Consequently, it plays a key role in our understanding of the physics of the internal structure of stars. Standard models of the Sun are theoretical representations of its present structure. These models include the best physical description of the fundamental processes which contribute to solar evolution and allow t... Title: Identification of Solar Acoustic Modes of Low Angular Degree and Low Radial Order Authors: Bertello, L.; Varadi, F.; Ulrich, R. K.; Henney, C. J.; Kosovichev, A. G.; García, R. A.; Turck-Chièze, S. Bibcode: 2000ApJ...537L.143B Altcode: We present evidence for the detection of low radial order (n<10) acoustic modes of low angular degree, l=0-2, in the 759 day long Global Oscillations at Low Frequency and Michelson Doppler Imager time series. We used Random-Lag Singular Cross-Spectrum Analysis, which searches for simultaneous oscillatory components in two or more time series. We have determined 11 modes in the range n=3-9, of which eight modes confirm the previous measurements by Toutain et al. and three modes of l=0 and n=3, 5, and 6 are reliably measured for the first time. The errors of frequency determination are also significantly reduced for several previously identified modes. New sound speed inversion results suggest that the effect of inhomogeneous initial composition of the Sun should be included in the standard solar model. Title: Erratum: Standard Solar Models in the Light of New Helioseismic Constraints. II. Mixing below the Convective Zone Authors: Brun, A. S.; Turck-Chièze, S.; Zahn, J. P. Bibcode: 2000ApJ...536.1005B Altcode: In the paper ``Standard Solar Models in the Light of New Helioseismic Constraints. II. Mixing below the Convective Zone'' by A. S. Brun, S. Turck-Chièze, and J. P. Zahn (525, 1032 [1999]), several corrections are required: 1. The words ``greater than'' just after equation (11) for the definition of rbcz should be removed. 2. The beginning of first sentence of the next paragraph should read: ``With the latitudinal dependence of the angular velocity at the base of the convection zone borrowed from Thompson et al. (1996), Ωbcz/2π=456-72x2-42x4 nHz,'' instead of ``Ωbcz>/2π=456-72x2- 42x4.'' 3. In the footnote to Table 1, ``Rbzc'' should be ``Rbcz,'' as it is appears for ``Tbcz'' in the same footnote. 4. In Table 2, in the ``Parameters'' column, ``i0'' should be ``Z0,'' as in Table 1. 5. In Table 3, ``Observaton'' should be ``Observation.'' The Press sincerely regrets these errors. Title: Comparison of Frequencies and Rotational Splittings of Solar Acoustic Modes of Low Angular Degree from Simultaneous MDI and GOLF Observations Authors: Bertello, L.; Henney, C. J.; Ulrich, R. K.; Varadi, F.; Kosovichev, A. G.; Scherrer, P. H.; Roca Cortés, T.; Thiery, S.; Boumier, P.; Gabriel, A. H.; Turck-Chièze, S. Bibcode: 2000ApJ...535.1066B Altcode: During the years 1996 through 1998 the Michelson Doppler Imager (MDI) and the Global Oscillations at Low Frequency (GOLF) experiments on the Solar and Heliospheric Observatory (SOHO) mission have provided unique and nearly uninterrupted sequences of helioseismic observations. This paper describes the analysis carried out on power spectra from 759 days of calibrated disk-averaged velocity signals provided by these two experiments. The period investigated in this work is from 1996 May 25 to 1998 June 22. We report the results of frequency determination of low-degree (l<=3) acoustic modes in the frequency range between 1.4 mHz and 3.7 mHz. Rotational splittings are also measured for nonradial modes up to 3.0 mHz. The power spectrum estimation of the signals is performed using classical Fourier analysis and the line-profile parameters of the modes are determined by means of a maximum likelihood method. All parameters have been estimated using both symmetrical and asymmetrical line profile-fitting formula. The line asymmetry parameter of all modes with frequency higher than 2.0 mHz is systematically negative and independent of l. This result is consistent with the fact that both MDI and GOLF data sets investigated in this paper are predominantly velocity signals, in agreement with previous results. A comparison of the results between the symmetric and asymmetric fits shows that there is a systematic shift in the frequencies for modes above 2.0 mHz. Below this frequency, the line width of the modes is very small and the time base of the data does not provide enough statistics to reveal an asymmetry. In general, the results show that frequency and rotational splitting values obtained from both the MDI and GOLF signals are in excellent agreement, and no significant differences exist between the two data sets within the accuracy of the measurements. Our results are consistent with a uniform rotation of the solar core at the rate of about 435 nHz and show only very small deviations of the core structure from the standard solar model. Title: Structure of the Solar Core: Effect of Asymmetry of Peak Profiles Authors: Basu, S.; Turck-Chièze, S.; Berthomieu, G.; Brun, A. S.; Corbard, T.; Gonczi, G.; Christensen-Dalsgaard, J.; Provost, J.; Thiery, S.; Gabriel, A. H.; Boumier, P. Bibcode: 2000ApJ...535.1078B Altcode: 2000astro.ph..1208B Recent studies have established that peaks in solar oscillation power spectra are not Lorentzian in shape but have a distinct asymmetry. Fitting a symmetric Lorentzian profile to the peaks, therefore, produces a shift in frequency of the modes. Accurate determination of low-frequency modes is essential to infer the structure of the solar core by inversion of the mode frequencies. In this paper we investigate how the changes in frequencies of low-degree modes obtained by fitting symmetric and asymmetric peak profiles change the inferred properties of the solar core. We use data obtained by the Global Oscillations at Low Frequencies (GOLF) project on board the SOHO spacecraft. Two different solar models and inversion procedures are used to invert the data in order to determine the sound speed in the solar core. We find that for a given set of modes no significant difference in the inferred sound speed results from taking asymmetry into account when fitting the low-degree modes. Title: Solar modelling: Theory and Verification Authors: Turck-Chièze, S.; Brun, A. S.; Garcia, R. A. Bibcode: 2000NuPhS..87..162T Altcode: After 30 years of investigation, the solar neutrino problem is still puzzling but the perspectives are extremely encouraging, due to the large improvements obtained on the experimental side including nuclear reaction rates, high statistics in neutrino detections, precise acoustic mode properties and hope to detect gravity modes. The present status, including the differences between neutrino predictions and neutrino flux detections, confirms the general features of solar modelling proposed in the sixties but reveals a rich field of Astrophysics and Particle Physics. The helioseismic investigation of the solar interior with the satellite SOHO begins to offer a complete verification of the solar structure, the introduction of dynamical effects will modify the neutrino emissions and the solar properties on rotation and magnetic field could appear important for the solution of the puzzle if the properties of the neutrinos (mass and magnetic moment) are revealed more complex than thought at the beginning Title: The Solar Neutrino Puzzle Authors: Turck-Chièze, S. Bibcode: 2000NuPhS..80..183T Altcode: Neutrino fluxes coming from the Sun are now measured on earth with improved accuracy. The predicted neutrino emissions in the solar core depend on fundamental nuclear and astrophysical properties which are nowadays better constrained by experiments. This paper is focused on the ighlights in these fields and on their perspectives Title: Analysis of asymmetric p-mode profiles in GOLF data Authors: Thiery, S.; Boumier, P.; Gabriel, A. H.; Bertello, L.; Lazrek, M.; García, R. A.; Grec, G.; Robillot, J. M.; Roca Cortés, T.; Turck-Chièze, S.; Ulrich, R. K. Bibcode: 2000A&A...355..743T Altcode: We show here evidence for the necessity of an asymmetric form in modelling the profile of an acoustic mode in the power spectral density. The analysis was performed on a 805-day series of GOLF data (l=0 to 3). The assumptions used for the fits are discussed and their consequences quantified, in particular for the optimum choice of the fitting spectral window. Values are given for the bias on the mode parameters (frequency, width, splitting) when using a Lorentzian fit. The bias depends on the degree l and on the frequency, and when taken into account leads to variations in the mode parameters with degree more consistent with theoretical expectations. Title: The tachocline and lithium history in solar-like stars Authors: Piau, L.; Turck-Chièze, S.; Brun, A. S. Bibcode: 2000ASPC..198..303P Altcode: 2000scac.conf..303P No abstract at ADS Title: Standard Solar Models in the Light of New Helioseismic Constraints. II. Mixing below the Convective Zone Authors: Brun, A. S.; Turck-Chièze, S.; Zahn, J. P. Bibcode: 1999ApJ...525.1032B Altcode: 1999astro.ph..6382B In previous work, we have shown that recent updated standard solar models cannot reproduce the radial profile of the sound speed at the base of the convective zone and fail to predict the photospheric lithium abundance. In parallel, helioseismology has shown that the transition from differential rotation in the convective zone to almost uniform rotation in the radiative solar interior occurs in a shallow layer called the tachocline. This layer is presumably the seat of a large-scale circulation and of turbulent motions. Here we introduce a macroscopic transport term in the structure equations that is based on a hydrodynamical description of the tachocline proposed by Spiegel & Zahn, and we calculate the mixing induced within this layer. We discuss the influence of different parameters that represent the tachocline thickness, the Brunt-Väisälä frequency at the base of the convective zone, and the time dependence of this mixing process along the Sun's evolution. We show that the introduction of such a process inhibits the microscopic diffusion by about 25%. Starting from models including a pre-main-sequence evolution, we obtain (1) a good agreement with observed photospheric chemical abundance of light elements such as 3He, 4He, 7Li, and 9Be; (2) a smooth composition gradient at the base of the convective zone; and (3) a significant improvement of the sound-speed square difference between the seismic Sun and the models in this transition region when we allow the photospheric heavy-element abundance to adjust, within the observational incertitude, as a result of the action of this mixing process. The impact on neutrino predictions is also discussed. Title: Power spectra comparison between GOLF and MDI velocity observations Authors: Henney, C. J.; Ulrich, R. K.; Bertello, L.; Bogart, R. S.; Bush, R. I.; Scherrer, P. H.; Palle, P. L.; Roca Cortes, T.; Turck-Chieze, S. Bibcode: 1999AAS...194.5617H Altcode: 1999BAAS...31..914H We present a comparison of the velocity power spectra between the GOLF and MDI instruments. In addition, this poster outlines work towards creating a GOLF-simulated signal utilizing MDI velocity images. The simulation of the GOLF signal is achieved by integrating spatially weighted masks with MDI LOI-proxy velocity images. The GOLF-simulated signal and a selection of additional spatially masked MDI velocity signals are compared with the observed GOLF signal for a 759 day period from May 25, 1996 through June 22, 1998. Ultimately, a cross-analysis process between GOLF and MDI signals could lead to an enhancement of our ability to detect low frequency solar oscillations. The signal-to-background ratio (S/B) for the GOLF and the spatially masked MDI velocity data is presented for low degree (l <= 3) and low frequency p-modes. We find that signals from both MDI and GOLF are beneficial for detecting low degree (l <= 3) and low frequency (< 2000 mu Hz) p-modes. For the frequency range and the signals compared in this poster, the GOLF signal has the highest S/B for l=0 p-modes. The S/B of the GOLF and MDI central region masked signals is good for detecting l=1 p-modes. For l >= 2 p-modes, the central region masked signals have the highest S/B of the power spectra compared here. In addition, the S/B of the preliminary GOLF-simulated signal is found to be more similar to the GOLF signal than the MDI LOI-proxy signal without spatial masking for the modes investigated here. Title: Power spectra comparison between GOLF and spatially masked MDI velocity signals Authors: Henney, C. J.; Ulrich, R. K.; Bertello, L.; Bogart, R. S.; Bush, R. I.; Scherrer, P. H.; Roca Cortés, T.; Turck-Chièze, S. Bibcode: 1999A&A...348..627H Altcode: The Global Oscillations at Low Frequency (GOLF) and the Michelson Doppler Imager (MDI) instruments aboard the Solar and Heliospheric Observatory (SOHO) give an excellent opportunity to search for solar low frequency oscillation modes previously undetected from ground based experiments. Presented here is a comparison of the velocity power spectra between the two instruments. In addition, this paper outlines work towards creating a GOLF-simulated signal utilizing MDI velocity images. The simulation of the GOLF signal is achieved by integrating spatially weighted masks with MDI full-disk Doppler images. The GOLF-simulated signal and a selection of additional spatially masked MDI velocity signals are compared with the observed GOLF signal for a 759 day period from May 25, 1996 through June 22, 1998. Ultimately, a cross-analysis process between GOLF and MDI signals could lead to an enhancement of our ability to detect low frequency solar oscillations. For low degree (l<= 3) and low frequency acoustic modes, the signal-to-background ratio between GOLF and the spatially masked MDI velocity data is compared here. Title: The solar neutrino puzzle: the way ahead Authors: Turck-Chièze, S. Bibcode: 1999NewA....4..325T Altcode: After a rapid review of the different activities which have contributed to the understanding of solar neutrino detections, we examine the present situation, the open questions and propose new directions of improvements. Title: The integrated magnetic field of the Sun as seen by GOLF on board SOHO Authors: García, R. A.; Boumier, P.; Charra, J.; Foglizzo, T.; Gabriel, A. H.; Grec, G.; Régulo, C.; Robillot, J. M.; Turck-Chièze, S.; Ulrich, R. K. Bibcode: 1999A&A...346..626G Altcode: An objective of the GOLF experiment (Global Oscillations at Low Frequencies) on-board the SOHO (Solar and Heliospheric Observatory) space mission was to measure the line-of-sight component of the disk-averaged magnetic field of the Sun. In this paper, a theoretical study of this observable is presented. The newly developed techniques are tested using simulated data series based on the observation of this experiment, and the sensitivity of GOLF to magnetic measurements is calculated. An average solar mean magnetic field of 0.120 +/- 0.002 G has been found corresponding to the minimum of solar activity by analyzing 26 days of full GOLF data. The power spectrum of this field is calculated and the main characteristics {are} described. Title: Solar oscillations: time analysis of the GOLF p-mode signal Authors: Renaud, C.; Grec, G.; Boumier, P.; Gabriel, A. H.; Robillot, J. M.; Roca Cortés, T.; Turck-Chièze, S.; Ulrich, R. K. Bibcode: 1999A&A...345.1019R Altcode: We determine the intrinsic phase lag of the GOLF data for the solar p-mode velocity deduced either from one of the narrow band photometers working alternatively on blue and red wing of the sodium lines. The timing of the ``blue wing'' velocity coming from the current GOLF data is given in respect to the ground-based observations. The phase lag for the ``blue'' velocity is 6 s in advance relatively to a velocity coming from a differential device. For individual p modes, the phase lag from the ``blue'' velocity to the ``red'' velocity are not in opposition of phase, as expected in a very simple solar model, but differs from 8(o) to 18(o) from the opposition, depending on the degree and the radial order of the acoustic mode. The measurement of the differential lag between the blue and red wings of the D lines may open a new way to monitor the temperature oscillations with the optical depth. Title: Results from the GOLF instrument on SOHO Authors: Gabriel, A. H.; Turck-Chièze, S.; García, R. A.; Pallé, P. L.; Boumier, P.; Thiery, S.; Baudin, F.; Grec, G.; Ulrich, R. K.; Bertello, L.; Roca Cortés, T.; Robillot, J. -M. Bibcode: 1999AdSpR..24..147G Altcode: An 800 day series of GOLF velocity data, with uniquely high continuity and stability, offers the best ever signal to noise ratio obtained in global Sun observations. Following meticulous efforts to provide reliable calibration, these data have been used for measurements of frequencies, line-widths and power in the p-modes, which are used for inversion to give the internal sound speed, for comparison with theoretical models. A search for g-modes is at present inconclusive, but has yielded two possible candidate frequencies. The analysis available today is regarded as preliminary and more complete methods are currently in hand. With the resumption of routine observations following the SOHO recovery, it is hoped that the data can be considerably extended, enabling changes with the solar cycle to be explored, as well as an extended g-mode search. Title: On the nature of the current GOLF p-mode signal Authors: Pallé, P. L.; Régulo, C.; Roca Cortés, T.; García, R. A.; Jiménez, A.; Boumier, P.; Gabriel, A.; Grec, G.; Robillot, J. M.; Turck-Chièze, S.; Ulrich, R. K.; SOI Team Bibcode: 1999A&A...341..625P Altcode: The GOLF experiment on board SOHO is designed to measure global oscillations of the disk-integrated sunlight with high sensitivity and with long term stability. The GOLF data is thus ideally suited for both the study of the p-mode spectrum and to address the search for gravity modes. Due to their occasional malfunction the project decided to stop the rotating polarizing elements at an optimum place in order to maintain a precise sequence of measurements with the highest possible duty cycle. This action means that subsequently GOLF only measures two monochromatic intensities {I}_b(+) and {I}_b(-) on the blue wing of the sodium doublet. In this work we investigate the nature of these signals separately and in combinations. Our method is to study the temporal relative phase relations between the low degree (l <= 3) p-mode signals derived from data sets obtained from simultaneous observations, both from other SOHO instruments (GOLF and SOI) and from Mark- I, the Tenerife station of the ground-based BiSON network. It is found that these signals are ``almost'' pure velocity signals. A simple model indicates that a contamination of a pure intensity-like signal of 14% amplitude would fully explain the true nature of the current GOLF signal. Moreover, it is found that the ratios, defined for other instruments (Mark-I, SOI and, by extension BiSON and IRIS), also have exactly the same nature as the GOLF ratio. Title: The Helioseismic Constraints on 7Li and 9Be from SOHO Authors: Brun, A. S.; Turck-Chièze, S. Bibcode: 1999ASPC..171...64B Altcode: 1999lcrr.conf...64B No abstract at ADS Title: Mixing Below the Solar Convective Zone Authors: Brun, A. S.; Turck-Chièze, S.; Zahn, J. -P. Bibcode: 1999ASPC..173..293B Altcode: 1999sstt.conf..293B No abstract at ADS Title: Power spectra comparison between GOLF and MDI velocity observations. Authors: Henney, C. J.; Ulrich, R. K.; Bertello, L.; Bogart, R. S.; Bush, R. I.; Scherrer, P. H.; Pallé, P. L.; Roca Cortés, T.; Turck-Chièze, S. Bibcode: 1999BAAS...31Q1237H Altcode: No abstract at ADS Title: The Solar Neutrino Puzzle Authors: Turck-Chieze, S. Bibcode: 1998tx19.confE.375T Altcode: After a rapid review of the different activities which have contributed to the understanding of solar neutrino detections, I shall present very precise helioseismic results which constrain the solar structure and begin to reveal the solar core. Sound speed, density and rotation profiles are new interesting tools to explore the central region in order to go beyond the standard solar model. Therefore helioseismology allows a better estimate of the emitted neutrino fluxes and of their related accuracy. Then I shall mention the open questions and propose new directions of improvements. Title: Standard Solar Models in the Light of New Helioseismic Constraints. I. The Solar Core Authors: Brun, A. S.; Turck-Chièze, S.; Morel, P. Bibcode: 1998ApJ...506..913B Altcode: 1998astro.ph..6272B In this paper, we examine a new, updated solar model that takes advantage of the recent reexamination of nuclear reaction rates and the microscopic diffusion of helium and heavy elements. Our best model fits the helioseismic data reasonably well, giving the base of the convective zone at Rbcz = 0.715, the photospheric helium in mass fraction as 0.243, and the sound-speed square difference between the Sun and the model as δc2/c2 < 1%. This model leads to a reestimate of neutrino fluxes, giving 7.18 SNU for the chlorine experiment, 127.2 SNU for the gallium detector, and 4.82 106 cm-2 s-1 for the 8B neutrino flux. Acoustic-mode predictions are also estimated. We then consider the radiative zone and discuss what we learn from such a model when confronted with the present helioseismic constraints from space experiments aboard SOHO. We present three models that respect these constraints and better fit the seismic observations by taking advantage of the known physical uncertainties--nuclear reaction rates, CNO abundances, and microscopic diffusion. We also study some current questions, such as the possibility of mixing in the nuclear core, the revision of the solar radius, and the influence of the solar age. We conclude that the standard model, inside its inherent uncertainties, is robust in light of the present acoustic-mode detection and that mixing in the core is not really favored, even though a proper understanding of the angular momentum evolution with time has not yet been reached. The initial solar helium abundance seems more and more constrained; this study supports an initial abundance between 0.273 and 0.277 in mass fraction. This analysis allows us to define minimal values for neutrino predictions, compatible with present seismic results. We note that a reduction of about 30% in chlorine and water detectors, which is more than half the discrepancy with the experimental results, is still supported by the present study. This work also emphasizes the fact that acoustic-mode determination does not put strong constraints on the nuclear plasma characteristics. Finally, we estimate g-mode frequencies in a range that may be accessible to the satellite SOHO; these results emphasize the substantially improved sensitivity of these modes to details of the nuclear solar core, and show the frequency dependence of these modes for the different models previously discussed. Title: Solar fusion cross sections Authors: Adelberger, Eric G.; Austin, Sam M.; Bahcall, John N.; Balantekin, A. B.; Bogaert, Gilles; Brown, Lowell S.; Buchmann, Lothar; Cecil, F. Edward; Champagne, Arthur E.; de Braeckeleer, Ludwig; Duba, Charles A.; Elliott, Steven R.; Freedman, Stuart J.; Gai, Moshe; Goldring, G.; Gould, Christopher R.; Gruzinov, Andrei; Haxton, Wick C.; Heeger, Karsten M.; Henley, Ernest; Johnson, Calvin W.; Kamionkowski, Marc; Kavanagh, Ralph W.; Koonin, Steven E.; Kubodera, Kuniharu; Langanke, Karlheinz; Motobayashi, Tohru; Pandharipande, Vijay; Parker, Peter; Robertson, R. G.; Rolfs, Claus; Sawyer, R. F.; Shaviv, N.; Shoppa, T. D.; Snover, K. A.; Swanson, Erik; Tribble, Robert E.; Turck-Chièze, Sylvaine; Wilkerson, John F. Bibcode: 1998RvMP...70.1265A Altcode: 1998astro.ph..5121A We review and analyze the available information on the nuclear-fusion cross sections that are most important for solar energy generation and solar neutrino production. We provide best values for the low-energy cross-section factors and, wherever possible, estimates of the uncertainties. We also describe the most important experiments and calculations that are required in order to improve our knowledge of solar fusion rates. Title: Time-correlation of the solar p-mode velocity signal from GOLF Authors: Gabriel, M.; Grec, G.; Renaud, C.; Gabriel, A. H.; Robillot, J. M.; Roca Cortes, T.; Turck-Chieze, S.; Ulrich, R. K. Bibcode: 1998A&A...338.1109G Altcode: Since the launch of SOHO, the Solar Heliospheric Orbital Observatory, the helioseismic observations are nearly uninterrupted. The GOLF instrument (A. Gabriel et al., 1997) measures the mean velocity integrated over the disk. The autocorrelation function of this velocity shows two main features: Firstly, the initial decrease of the peak amplitudes is much faster than expected from the width of the most powerful lines and %!second secondly it does not %!go decrease to zero for large times. These two features have been studied using the model of stochastically excited oscillators.The second one can also be understood on the basis of a completely general discussion. We show that the fast initial decrease of the peak amplitudes results from the departure of the mode frequencies from the values predicted by the first order asymptotic theory (the modes are not equidistant) and that the damping time of the modes has only a small influence. The non vanishing amplitudes at large times result either from the presence of a periodic non-stochastic component in the signal or from the stochastic nature of the excitation. Further tests have shown that the second possibility is the right one. This result gives a new argument in favor of the stochastic excitation of solar p-modes. The use of the ACF also suggests a new method to study line profiles which has been tested for radial modes and Lorentz profiles. Title: High-Frequency Peaks in the Power Spectrum of Solar Velocity Observations from the GOLF Experiment Authors: García, R. A.; Pallé, P. L.; Turck-Chièze, S.; Osaki, Y.; Shibahashi, H.; Jefferies, S. M.; Boumier, P.; Gabriel, A. H.; Grec, G.; Robillot, J. M.; Roca Cortés, T.; Ulrich, R. K. Bibcode: 1998ApJ...504L..51G Altcode: The power spectrum of more than 630 days of full-disk solar velocity data, provided by the GOLF spectrophotometer aboard the Solar and Heliospheric Observatory, has revealed the presence of modelike structure well beyond the acoustic cutoff frequency for the solar atmosphere (νac~5.4 mHz). Similar data produced by full-disk instruments deployed in Earth-based networks (BiSON and IRIS) had not shown any peak structure above νac: this is probably due to the higher levels of noise that are inherent in Earth-based experiments. We show that the observed peak structure (νac<=ν<=7.5 mHz) can be explained by a simple two-wave interference model if the high-frequency waves are partially reflected at the back side of the Sun. Title: Composition and Opacity in the Solar Interior Authors: Turck-Chieze, Sylvaine Bibcode: 1998SSRv...85..125T Altcode: Detailed abundances of elements from hydrogen up to iron are necessary to perform a precise model of the solar structure. Most of them have been deduced from photospheric observed values, some others from the meteoritic composition. Nowadays, thanks to helioseismic constraints, they seem more and more under control. Title: Are solar acoustic modes correlated? Authors: Foglizzo, T.; Garcia, R. A.; Boumier, P.; Charra, J.; Gabriel, A. H.; Grec, G.; Robillot, J. M.; Roca Cortes, T.; Turck-Chieze, S.; Ulrich, R. K. Bibcode: 1998A&A...330..341F Altcode: 1997astro.ph..9095F We have studied the statistical properties of the energy of individual acoustic modes, extracted from 310 days of GOLF data near the solar minimum. The exponential distribution of the energy of each mode is clearly seen. The modes are found to be uncorrelated with a partial 0.6% accuracy, thus supporting the hypothesis of stochastic excitation by the solar convection. Nevertheless, the same analysis performed on the same modes just before the solar maximum, using IPHIR data, rejects the hypothesis of no correlation at a 99.3% confidence level. A simple model suggests that 31.3partialm 9.4% of the energy of each mode is coherent among the modes studied in IPHIR data, correponding to a mean correlation of 10.7partialm 5.9%. Title: Sensitivity of the Sound Speed to the Physical Processes Included in the Standard Solar Model Authors: Turck-Chièze, S.; Basu, S.; Berthomieu, G.; Bonanno, A.; Brun, A. S.; Christensen-Dalsgaard, J.; Gabriel, M.; Morel, P.; Provost, J.; Turcotte, S.; GOLF Team Bibcode: 1998ESASP.418..555T Altcode: 1998soho....6..555T The accuracy of the present seismic data allows us to check the solar internal sound speed down to the core. This is a great support to check the hypothesis of the classical stellar evolution and to predict the neutrino fluxes. The interpretation of these measurements supposes an accurate determination of the structure of the standard solar model as a first step. It is why a continuing effort has been devoted to the knowledge of the physical quantities included in this framework. In this poster we present 6 different solar models calculated by different groups of the GOLF consortium. These models include the most recent progress in atomic physics and nuclear physics. Then, we discuss the sensitivity of the sound speed difference, between GOLF+MDI observations and models, to different ingredients, in peculiar to the opacity coefficients and the determination of the solar age. Title: Stability Study of the GOLF Blue Wing Working Cycle Authors: Robillot, J. M.; Turck-Chieze, S.; Garcia, R. A.; Boumier, P.; Charra, J.; Ulrich, R. K.; Gabriel, A.; Grec, G.; Roca Cortes, T. Bibcode: 1998ESASP.418..317R Altcode: 1998soho....6..317R The GOLF experiment is a resonant scattering spectrophotometer in flight on board the SOHO mission, originally designed to measure the intensity of the solar radiation at 4 selected positions within the sodium doublet (D1 at λ 5896 and D2 at λ 5890 AA). Each position was determined by a modulated magnetic field and a combination of rotating polarizers (see Gabriel et al. 1995, 1997 for a full description of the instrument). Due to occasional malfunctions of the polarizing element that allows to switch between the two wings of the solar profile, it was decided to stop the mechanism in a safety position. Thus, only two monochromatic intensities, Ib+ and Ib- are measured but a duty cycle close to 100 % is achieved. After more than two years of blue wing measurements we show the long term stability of the GOLF experiment and we discuss their impact on the new derived velocity. Title: Report from Working Group Session 3: Solar Structure: Models and Inversions Authors: Turck-Chièze, S.; Basu, S. Bibcode: 1998ESASP.418..573T Altcode: 1998soho....6..573T No abstract at ADS Title: Macroscopic Processes in the Solar Interior Authors: Brun, A. S.; Turck-Chièze, S.; Zahn, J. P. Bibcode: 1998ESASP.418..439B Altcode: 1998astro.ph..7090B; 1998soho....6..439B With the recent results of heliseismology aboard SOHO, the solar models are more and more constrained (Brun, Turck-Chièze et Morel 1998) . New physical processes, mainly connected to macroscopic motions, must be introduced to understand these news observations. In this poster, we present solar models with such macroscopic motions, as turbulent pressure in the outer layers, mixing due to the tachocline (Spiegel and Zahn 1992), and some mixing in the core (Morel and Schatzman 1996). From our results, we could say that: (1) Mixing in the core is unlikely (δ c2/c2 > 2%) (2) Turbulent pressure improves the absolute value of the acoustic modes frequencies (~5 μ Hz at 4 mHz) (3) And mixing in a tachocline of thickness of 0.05 plus or minus 0.03 Rodot (Corbard et al. 1997) looks promising. Title: Composition and Opacity in the Solar Interior Authors: Turck-Chièze, S. Bibcode: 1998sce..conf..125T Altcode: No abstract at ADS Title: High-Frequency Signals in the Power Spectrum of Integrated Solar Velocity Observations from the GOLF Experiment Authors: Garcia, R. A.; Pallé, P. L.; Turck-Chièze, S.; Osaki, Y.; Shibahashi, H.; Jefferies, S.; GOLF Team Bibcode: 1998ESASP.418..177G Altcode: 1998soho....6..177G The power spectrum of ~630 days of full-disk solar velocity data, provided by the GOLF spectrophotometer aboard SOHO, has revealed the presence of mode-like structure well beyond the acoustic cut-off frequency for the solar atmosphere (nuac ~5.4 mHz). This kind of structure has already been observed in intermediate and high spatial resolution oscillation data (Duvall et al. 1991), but never before in integrated data like BiSON or IRIS. This is probably due to the higher level of noise that are inherent to the earth-based experiments. In this contribution, we analyse the observed peak structure (nuac < ν < 7.5 mHz) and we describe the theoretical analysis of such signal. Title: First Results on it P Modes from GOLF Experiment Authors: Lazrek, M.; Baudin, F.; Bertello, L.; Boumier, P.; Charra, J.; Fierry-Fraillon, D.; Fossat, E.; Gabriel, A. H.; García, R. A.; Gelly, B.; Gouiffes, C.; Grec, G.; Pallé, P. L.; Pérez Hernández, F.; Régulo, C.; Renaud, C.; Robillot, J. -M.; Roca Cortés, T.; Turck-Chièze, S.; Ulrich, R. K. Bibcode: 1997SoPh..175..227L Altcode: The GOLF experiment on the SOHO mission aims to study the internal structure of the Sun by measuring the spectrum of global oscillations in the frequency range 10-7 to 10-2 Hz. Here we present the results of the analysis of the first 8 months of data. Special emphasis is put into the frequency determination of the p modes, as well as the splitting in the multiplets due to rotation. For both, we show that the improvement in S/N level with respect to the ground-based networks and other experiments is essential in achieving a very low-degree frequency table with small errors ∼ 2 parts in 10-5). On the other hand, the splitting found seems to favour a solar core which does not rotate slower than its surface. The line widths do agree with theoretical expectations and other observations. Title: First View of the Solar Core from GOLF Acoustic Modes Authors: Turck-Chièze, S.; Basu, S.; Brun, A. S.; Christensen-Dalsgaard, J.; Eff-Darwich, A.; Lopes, I.; Pérez Hernández, F.; Berthomieu, G.; Provost, J.; Ulrich, R. K.; Baudin, F.; Boumier, P.; Charra, J.; Gabriel, A. H.; Garcia, R. A.; Grec, G.; Renaud, C.; Robillot, J. M.; Roca Cortés, T. Bibcode: 1997SoPh..175..247T Altcode: After 8 months of nearly continuous measurements the GOLF instrument, aboard SOHO, has detected acoustic mode frequencies of more than 100 modes, extending from 1.4 mHz to 4.9 mHz. In this paper, we compare these results with the best available predictions coming from solar models. To verify the quality of the data, we examine the asymptotic seismic parameters; this confirms the improvements achieved in solar models during the last decade. Title: Performance and Early Results from the GOLF Instrument Flown on the SOHO Mission Authors: Gabriel, A. H.; Charra, J.; Grec, G.; Robillot, J. -M.; Roca Cortés, T.; Turck-Chièze, S.; Ulrich, R.; Basu, S.; Baudin, F.; Bertello, L.; Boumier, P.; Charra, M.; Christensen-Dalsgaard, J.; Decaudin, M.; Dzitko, H.; Foglizzo, T.; Fossat, E.; García, R. A.; Herreros, J. M.; Lazrek, M.; Pallé, P. L.; Pétrou, N.; Renaud, C.; Régulo, C. Bibcode: 1997SoPh..175..207G Altcode: GOLF in-flight commissioning and calibration was carried out during the first four months, most of which represented the cruise phase of SOHO towards its final L1 orbit. The initial performance of GOLF is shown to be within the design specification, for the entire instrument as well as for the separate sub-systems. Malfunctioning of the polarising mechanisms after 3 to 4 months operation has led to the adoption of an unplanned operating sequence in which these mechanisms are no longer used. This mode, which measures only the blue wing of the solar sodium lines, detracts little from the detection and frequency measurements of global oscillations, but does make more difficult the absolute velocity calibration, which is currently of the order of 20%. Data continuity in the new mode is extremely high and the instrument is producing exceptionally noise-free p-mode spectra. The data set is particularly well suited to the study of effects due to the excitation mechanism of the modes, leading to temporal variations in their amplitudes. The g modes have not yet been detected in this limited data set. In the present mode of operation, there are no indications of any degradation which would limit the use of GOLF for up to 6 years or more. Title: Tri-Phonic Helioseismology: Comparison of Solar P Modes Observed by the Helioseismology Instruments Aboard SOHO Authors: Toutain, T.; Appourchaux, T.; Baudin, F.; Fröhlich, C.; Gabriel, A.; Scherrer, P.; Andersen, B. N.; Bogart, R.; Bush, R.; Finsterle, W.; García, R. A.; Grec, G.; Henney, C. J.; Hoeksema, J. T.; Jiménez, A.; Kosovichev, A.; Roca Cortés, T.; Turck-Chièze, S.; Ulrich, R.; Wehrli, C. Bibcode: 1997SoPh..175..311T Altcode: The three helioseismology instruments aboard SOHO observe solar p modes in velocity (GOLF and MDI) and in intensity (VIRGO and MDI). Time series of two months duration are compared and confirm that the instruments indeed observe the same Sun to a high degree of precision. Power spectra of 108 days are compared showing systematic differences between mode frequencies measured in intensity and in velocity. Data coverage exceeds 97% for all the instruments during this interval. The weighted mean differences (V-I) are −0.1 µHz for l=0, and −0.16 µHz for l=1. The source of this systematic difference may be due to an asymmetry effect that is stronger for modes seen in intensity. Wavelet analysis is also used to compare the shape of the forcing functions. In these data sets nearly all of the variations in mode amplitude are of solar origin. Some implications for structure inversions are discussed. Title: Diagnostics of the External Physical Processes from Global Oscillations of Solar-like Stars Authors: Lopes, Ilídio; Turck-Chieze, Sylvaine; Michel, Eric; Goupil, Marie-Jo Bibcode: 1997ApJ...480..794L Altcode: We present and discuss a method to determine the phase shift of the global acoustic oscillations of solar-like stars. This quantity can be used to infer the main contributors of the mechanical behavior of the acoustic waves in the outer layers of the star as far as the energy transport and the photospheric helium abundance are concerned. The phase shift is obtained for the Sun and for a specific candidate, β Virginis (HD 102870), in the perspective of interpreting the next generation of asteroseismology measurements. It is found that the signature of the ionization of helium is better determined in a solar-like star slightly more massive than the Sun and that this analysis can provide a very useful indicator of the photospheric helium content, particularly in clusters. We also find a noticeable sensitivity to the value of the mixing-length parameter. Title: Performance and first results from the GOLF instrument on SoHO Authors: Gabriel, A. H.; Charra, J.; Grec, G.; Robillot, J. -M.; Roca Cortés, T.; Turck-Chièze, S.; Ulrich, R.; Baudin, F.; Bertello, L.; Boumier, P.; Decaudin, M.; Dzitko, H.; Foglizzo, T.; Fossat, E.; García, R. A.; Herreros, J. M.; Lazrek, M.; Pallé, P. L.; Pétrou, N.; Renaud, C.; Régulo, C. Bibcode: 1997IAUS..181...53G Altcode: No abstract at ADS Title: Actual Status and Early Results from GOLF Experiment on-board SOHO Authors: Roca Cortes, T.; Gabriel, A. H.; Charra, J.; Grec, G.; Ulrich, R. K.; Turck-Chieze, S.; Robillot, J. M.; Boumier, P.; Regulo, C.; Baudin, F.; Lazrek, M.; Garcia, R. A.; Palle, P. L.; GOLF Team Bibcode: 1997ASPC..118..249R Altcode: 1997fasp.conf..249R GOLF is a resonant scattering spectrophotomer which is flying onboard SOHO. The first four months were dedicated to the commissioning and calibration of the instrument which led to the conclusion of a performance within design specification at system and subsystem levels. However, mal-functioning of the polarising mechanisms at the end of this period led to the adoption of an unplanned operating sequence in which the mechanisms are no longer used. This photometric mode, which measures at two points on the blue wing of the solar sodium lines, has very little effect on the possibility of reaching the first objective of the mission: measuring the solar spectrum of normal modes. However, the precise calibration procedure to transform the actual measurements into velocity is not trivial. The actual operating mode allows the obtention of continuous data without interruptions which is producing exceptionally noise-free p-mode spectra. Although this spectrum is being studied, the data accumulated do not allow a positive detection of the g-mode spectrum yet. On the other hand, the present mode of operation do not show any indication of degradation which could limit its use for up to 6 years or more of operation. Title: Solar Neutrinos and the Solar Model Authors: Turck-Chieze, S. Bibcode: 1997ndmu.conf..147T Altcode: No abstract at ADS Title: GOLF results: today's view on the solar modes Authors: Grec, C.; Turck-Chièze, S.; Lazrek, M.; Roca Cortés, T.; Bertello, L.; Baudin, F.; Boumier, P.; Charra, J.; Fierry-Fraillon, D.; Fossat, E.; Gabriel, A. H.; Garcia, R. A.; Gelly, B.; Gouiffes, C.; Régulo, C.; Renaud, C.; Robillot, J. M.; Ulrich, R. K. Bibcode: 1997IAUS..181...91G Altcode: No abstract at ADS Title: L'héliosismologie. Authors: Lehoucq, R.; Turck-Chieze, S. Bibcode: 1996LAstr.110..146L Altcode: No abstract at ADS Title: The Sun as a laboratory: a classical or a non classical Sun? Authors: Turck-Chieze, S. Bibcode: 1996NuPhS..48..350T Altcode: In this review, I first mention the improvements in nuclear or plasma physics which may still substantially reduce the discrepancy between neutrino predictions and observed neutrino fluxes. Then, I examine the questions suggested by the helioseismic present results and the theoretical improvements which are planned to perform. Finally, I present the next generation of the spatial experiments and the potentiality we wait from their results. Title: Global Oscillations at Low Frequency from the SOHO Mission (GOLF) Authors: Gabriel, A. H.; Grec, G.; Charra, J.; Robillot, J. -M.; Roca Cortés, T.; Turck-Chièze, S.; Bocchia, R.; Boumier, P.; Cantin, M.; Cespédes, E.; Cougrand, B.; Crétolle, J.; Damé, L.; Decaudin, M.; Delache, P.; Denis, N.; Duc, R.; Dzitko, H.; Fossat, E.; Fourmond, J. -J.; García, R. A.; Gough, D.; Grivel, C.; Herreros, J. M.; Lagardère, H.; Moalic, J. -P.; Pallé, P. L.; Pétrou, N.; Sanchez, M.; Ulrich, R.; van der Raay, H. B. Bibcode: 1995SoPh..162...61G Altcode: The GOLF experiment on the SOHO mission aims to study the internal structure of the sun by measuring the spectrum of global oscillations in the frequency range 10−7 to 10−2 Hz. Bothp andg mode oscillations will be investigated, with the emphasis on the low order long period waves which penetrate the solar core. The instrument employs an extension to space of the proven ground-based technique for measuring the mean line-of-sight velocity of the viewed solar surface. By avoiding the atmospheric disturbances experienced from the ground, and choosing a non-eclipsing orbit, GOLF aims to improve the instrumental sensitivity limit by an order of magnitude to 1 mm s−1 over 20 days for frequencies higher than 2.10−4 Hz. A sodium vapour resonance cell is used in a longitudinal magnetic field to sample the two wings of the solar absorption line. The addition of a small modulating field component enables the slope of the wings to be measured. This provides not only an internal calibration of the instrument sensitivity, but also offers a further possibility to recognise, and correct for, the solar background signal produced by the effects of solar magnetically active regions. The use of an additional rotating polariser enables measurement of the mean solar line-of-sight magnetic field, as a secondary objective. Title: The role of abundances in the solar interior models Authors: Turck-Chieze, S. Bibcode: 1995AdSpR..15g..85T Altcode: 1995AdSpR..15...85T I would like to show, in this review, what we have learned on the detailed determination of the element abundances, from the observables of the solar interior. I shall separate the discussion in two parts, the knowledge of the heavy elements and the knowledge of the helium content. The heavy elements determination is necessary to perform a complete calculation of solar evolution for the nuclear energy production (about 1-1.5%) and the transfer of energy in the radiative regions. On the contrary, there is no assumption on the helium content in a solar model (because it is not measured in the photosphere) and I would like to comment on the two ways to adjust it: the total solar evolution calculation which is constrained by the present knowledge of the solar luminosity and age and the extraction of the acoustic frequency phases of high degree which are sensitive to the helium ionization zone. Title: The Screened Nuclear Reaction Rates and the Solar Neutrino Puzzle Authors: Dzitko, H.; Turck-Chieze, S.; Delbourgo-Salvador, P.; Lagrange, C. Bibcode: 1995ApJ...447..428D Altcode: This paper reexamines the nuclear reaction rates used for hydrogen burning in the classical framework of stellar evolution. The screening effect is discussed, and the formalisms generally used appear not accurate enough for the determination of the solar neutrino fluxes. So we analyze screening with the more realistic potential suggested by Mitler. We compare the first-order description which allows factorization of the screening correction with a complete calculation in which an ellipsoidal charge distribution around reacting ions is introduced. Since the radial deformation of the charge distribution appears to have a small effect and is of the same order as and of opposite sign to the dynamical effect of the surrounding ions, we conclude that the factorized prescription of Mitler seems really easy to implement and appropriate within 2% accuracy for the whole hydrogen-burning phase and stellar masses between 0.6 and 20 Msun. It leads to an enhancement factor of the reaction rates located between those of Salpeter weak screening and Graboske et al. intermediate screening. Then we consider each reaction rate of the p-p chain, and it appears that two reactions may still be modified significantly beyond the "conventional error bar": the electronic capture on 7Be and the proton interaction on the same nucleus, both of which influence the 8B neutrino flux. Considering reasonable variations of the nuclear reaction rates of the p-p chains, compatible with the present experimental and theoretical situation, the solar neutrino discrepancy between experiments and predictions could be considerably reduced. Title: Corot: a Space Project Devoted to the Study of Convection and Rotation in Stars Authors: Catala, C.; Auvergne, M.; Baglin, A.; Bonneau, F.; Magnan, A.; Vuillemin, A.; Goupil, M. J.; Michel, E.; Boumier, P.; Dzitko, H.; Gabriel, A.; Gautier, D.; Lemaire, P.; Mangeney, A.; Mosser, B.; Turck-Chiéze, S.; Zahn, J. P. Bibcode: 1995ESASP.376b.549C Altcode: 1995soho....2..549C; 1995help.confP.549C No abstract at ADS Title: A Second Order Asymptotic Expression Applied to the Low Degree Acoustic Mode Predictions Authors: Lopes, I.; Turck-Chieze, S. Bibcode: 1995ASPC...76..160L Altcode: 1995gong.conf..160L No abstract at ADS Title: Solar Modeling: Critical Look and Neutrino Puzzle Authors: Turck-Chieze, S.; Dzitko, H.; Lopes, I. Bibcode: 1995ASPC...76..116T Altcode: 1995gong.conf..116T No abstract at ADS Title: Study of the Screening Formalisms for Stellar Evolution Codes Authors: Dzitko, H.; Turck-Chieze, S.; Delbourgo-Salvador, P.; Lagrange, C. Bibcode: 1995ASPC...76..172D Altcode: 1995gong.conf..172D No abstract at ADS Title: COROT: A Proposal to Study Stellar Convection and Internal Rotation Authors: Catala, C.; Mangeney, A.; Gautier, D.; Auvergne, M.; Baglin, A.; Goupil, M. J.; Michel, E.; Zahn, J. P.; Magnan, A.; Vuillemin, A.; Boumier, P.; Gabriel, A.; Lemaire, P.; Turck-Chieze, S.; Dzitko, H.; Mosser, B.; Bonneau, F. Bibcode: 1995ASPC...76..426C Altcode: 1995gong.conf..426C No abstract at ADS Title: The second order asymptotic theory for the solar and stellar low degree acoustic mode predictions Authors: Lopes, I.; Turck-Chieze, S. Bibcode: 1994A&A...290..845L Altcode: We discuss the new asymptotic formulae, obtained by Tassoul and Vorontsov without the Cowling approximation, for the acoustic modes of low degree. We deduce second-order asymptotic expressions which recover the absolute value of the solar calculated eigenfrequencies within 10μHz for degrees lower than 12 and frequencies between 1mHz<=ν<=5mHz. This result is compared with the previous ones obtained in a first or second-order asymptotic theories. The different seismic parameters: {DELTA}ν_l,n_ , δ_2nu_l,n_ and δν_l,n_ , the phase shift α and its derivative β_l,n_ are also determined and the influence of the different physical processes are emphasized. Title: Studies on the Central Part of the Solar Model and Incidences on Stellar Evolution Authors: Dzitko, H.; Turck-Chièze, S. Bibcode: 1994emsp.conf....3D Altcode: No abstract at ADS Title: The spatial GOLF project Authors: Turck-Chieze, S. Bibcode: 1994esa..conf..532T Altcode: 1994IAUCo.147..532T No abstract at ADS Title: Analysis of the screening formalisms in solar and stellar conditions Authors: Dzitko, H.; Turck-Chieze, S.; Delbourgo-Salvador, P.; Lagrange, Ch. Bibcode: 1994esa..conf..601D Altcode: 1994IAUCo.147..601D No abstract at ADS Title: Toward a Unified Classical Model of the Sun: On the Sensitivity of Neutrinos and Helioseismology to the Microscopic Physics Authors: Turck-Chieze, S.; Lopes, J. Bibcode: 1994snft.book...63T Altcode: No abstract at ADS Title: The solar interior Authors: Turck-Chièze, S.; Däppen, W.; Fossat, E.; Provost, J.; Schatzman, E.; Vignaud, D. Bibcode: 1993PhR...230...57T Altcode: This report confronts the different aspects of the solar interior from the experimental and theoretical points of view, discussing photospheric abundances, neutrinos and acoustic mode measurements. The theoretical approach mainly concerns the classical framework of stellar evolution, nevertheless, particle interpretation of the data and astrophysical solutions invoked in the last 10 years are coherently examined. Title: Toward a Unified Classical Model of the Sun: On the Sensitivity of Neutrinos and Helioseismology to the Microscopic Physics Authors: Turck-Chieze, Sylvaine; Lopes, Ilidio Bibcode: 1993ApJ...408..347T Altcode: This paper focuses mainly on the neutrino puzzle and discusses the point of view that neutrinos and helioseismology are two complementary probes of the solar interior. We first analyze the physical differences noticed between already published solar models and their consequences for neutrino predictions. We propose new results on the solar neutrino predictions and acoustic mode frequencies for l = 0-150, in the classical framework of stellar evolution. We quantify the influence of precise composition, nuclear reaction rates, screening effect, and opacity calculations on both neutrino and acoustic mode frequency predictions. Our present predictions are 6.4 +/- 1.4 SNU for the chlorine experiment, 4.4 +/- 1.1 x 10 exp 6/sq cm/s for the water detector, and 122.5 +/- 7 SNU for the gallium detector. Title: Solar modelling and the neutrino puzzle the astrophysical point of view Authors: Turck-Chièze, S. Bibcode: 1993NuPhS..31..129T Altcode: After short comments on the neutrino puzzle and the energy balance, I shall discuss the impact of the improved ingredients of the solar modelling on the solar structure, the predicted neutrino fluxes and the acoustic frequencies determination. Progresses in the understanding of the acoustic frequencies are clear and reinforce the idea that the classical framework is justified, as a first approximation. Regarding the neutrino problem, even if each modification has some impact on different neutrino sources, altogether, they only slightly reduce the present discrepancy, so we conclude that the main source of the discrepancy is not yet discovered. As far as there is no clear disagreement between the different experiments, I suggest directions of investigations for the near future concerning the nuclear region where the nuclear reaction rates must be revisited and concerning phenomena not yet included in solar modelling. Title: Theoretical review Authors: Turck-Chièze, S. Bibcode: 1993paas.conf...75T Altcode: No abstract at ADS Title: Microscopic physics in the solar standard model Authors: Lopes, I.; Turck-Chieze, S. Bibcode: 1993ASPC...40...51L Altcode: 1993IAUCo.137...51L; 1993ist..proc...51L No abstract at ADS Title: Screening effect in solar conditions. Authors: Dzitko, H.; Delbourgo-Salvador, P.; Lagrange, C.; Turck-Chièze, S. Bibcode: 1993oee..conf..388D Altcode: No abstract at ADS Title: Comments on solar modelling Authors: Turck-Chieze, Sylvaine Bibcode: 1992NuPhS..28..116T Altcode: In this contribution, I compare what we learn from detected solar neutrino fluxes on earth and what we learn from helioseismology. Contrary to the first impression that helioseismology is in better agreement with theoretical predictions, I insist on the fact that the deduced uncertainty on the thermodynamical quantities is of the same order. Then I take the example of cosmions to examine the lesson of extra hypothesis on classical framework of stellar evolution in order to conclude on the astrophysical perspectives and the problems open. Title: The classical solar model and beyond this framework. Authors: Turck-Chièze, S. Bibcode: 1992pnap.conf....3T Altcode: From the comparison of recent updated solar model predictions, the extreme sensitivity of the 8B neutrino flux to opacity coefficients, to some specific reactions and to the screening effect is once more illustrated. Title: A Critical Look at Cosmions Authors: Kaplan, Jean; Martin de Volnay, Francois; Tao, Charling; Turck-Chieze, Sylvaine Bibcode: 1991ApJ...378..315K Altcode: A thorough numerical investigation of the cosmion hypothesis as a solution to the solar neutrino puzzle was performed using the Saclay solar evolution code. The ensuing constraints on cosmion parameters appear as domains in the plane of cosmion-proton cross section versus cosmion mass. Various hypotheses on cosmion couplings are considered. Comparison with available experimental data on direct dark matter detection excludes most of the domain in the 'vector' case. In the 'axial' case the results provide useful hints for experiments. The effect of cosmions on the sound speed near the center of the sun, confronted with present knowledge and data on helioseismology, does not improve the comparison between standard predictions and helioseismological inversion. Title: A critical look at cosmions. Authors: Kaplan, J.; de Volnay, F. M.; Tao, C.; Turck-Chièze, S. Bibcode: 1990clac.book.....K Altcode: The authors have performed a numerical investigation of the cosmion hypothesis as a solution to the solar neutrino puzzle, using the Saclay solar evolution code. The ensuing constraints on cosmion parameters appear as domains in the plane of cosmion-proton cross-section versus cosmion mass. Various hypothesis on cosmion couplings are considered. Comparison with available experimental data on direct dark matter detection excludes most of the domain in the "vector" case. In the "axial" case the results provide useful hints for experiments. Finally the effect of cosmions on the sound speed near the center of the sun is confronted with present knowledge and data on helioseismology. Title: WIMPS and Solar Evolution Code Authors: Giraud-Heraud, Yannick; Kaplan, Jean; de Volnay, Francois Martin; Tao, Charling; Turck-Chieze, Sylvaine Bibcode: 1990SoPh..128...21G Altcode: 1990IAUCo.121P..21G The Saclay solar evolution code is used to check the effect of WIMPs on solar evolution. In this paper we study the effects of various types of Cosmion-matter interactions, give constraints on the crosssections compatible with the measured neutrino rate of 2 SNU on chlorine, and relate these constraints to ongoing dark matter detection experiments. Title: Metallicity, opacity coefficients and the solar standard model Authors: Courtaud, D.; Damamme, G.; Genot, E.; Vuillemin, M.; Turck-Chieze, Sylvaine Bibcode: 1990SoPh..128...49C Altcode: 1990IAUCo.121P..49C We discuss the effect of the uncertainties affecting the opacities on the derived characteristics of the Sun. We consider two sources of uncertainty: the relative composition of the Sun at birth and the difference between two opacity calculations. As an illustration, we discuss the effect of the choice of photospheric or meteoritic iron abundance on the predicted chlorine neutrino capture rate and present comparisons between the Los Alamos and Limeil opacity calculations. Title: Progress in solar modeling Authors: Turck-Chieze, S. Bibcode: 1990nep..conf..571T Altcode: No abstract at ADS Title: On the Accuracy of Solar Modelling Authors: Turck-Chièze, Sylvaine Bibcode: 1990ASSL..159..125T Altcode: 1990insu.conf..125T; 1990IAUCo.121..125T No abstract at ADS Title: Revisiting the Standard Solar Model Authors: Turck-Chieze, S.; Cahen, S.; Casse, M.; Doom, C. Bibcode: 1988ApJ...335..415T Altcode: The authors investigate the mutual consistency between contemporary standard solar models, based on the recent Los Alamos opacity tables. Satisfactory agreement is found among these models concerning the helium content and the neutrino capture rates, considering the extreme sensitivity of the 8B neutrino flux to central conditions of the Sun. The authors' reference model leads to a solar helium content of 0.276±0.012 by mass fraction, a capture rate of 5.8±1.3 SNU on 37Cl and 125±5 SNU on 71Ga. Title: High mass loss in the young Sun! Authors: Turck-Chieze, S.; Daeppen, W.; Casse, M. Bibcode: 1988ESASP.286..629T Altcode: 1988ssls.rept..629T The consequences of a possible mass loss in the early main sequence stage of solar type stars are investigated. Special attention is given to the Sun, the constraints from surface abundances and p-mode observations are taken into account. Only a total mass loss smaller than 0.2 Msun seems to be consistent with the observations. Though the ensuing modifications of the internal structure and the cosmological consequences are very small, the 3He, 7Li, 9Be surface abundances are significantly modified. Title: Modelling the variation of solar p-mode frequencies. Authors: Daeppen, W.; Gough, Douglas O.; Turck-Chieze, S. Bibcode: 1988ESASP.286..511D Altcode: 1988ssls.rept..511D The authors present a Green's function technique to study long-term variations of the Sun (with characteristic time scales from one month to millions of years). The method is the combination of two previous analyses carried out independently by Gough and by Däppen. Their study has been motivated by the recent observational progress on solar p-mode frequency variations. Title: The interior of the Sun: from observations to theory. Authors: Turck-Chièze, S. Bibcode: 1988ffnp.conf..165T Altcode: Precise observations (surface abundances, neutrino fluxes detection, seismology) and laboratory measurements (nuclear reactions rates) constrain and guide the standard model of the Sun and by this way test the first stage of stellar evolution. A review of the situation is proposed enlightened by the agreement between the most detailed and updated standard models published. A discussion on the incidence of non-standard physics is also given. Title: Étude de l'électrodésintégration du deutérium ²H(ee'p)n dans un large domaine d'inélasticité et pour des impulsions de recul du neutron allant de 0 à 500 MeV/c Title: Étude de l'électrodésintégration du deutérium ²H(ee'p)n dans un large domaine d'inélasticité et pour des impulsions de recul du neutron allant de 0 à 500 MeV/c Title: Study on the deuterium electrodecay ²H(ee'p)n in a large inelasticity range and for recoil neutron momenta from 0 to 500 MeV/c; Authors: Turck-Chièze, Sylvaine Bibcode: 1985PhDT........65T Altcode: No abstract at ADS