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Author name code: bappu
ADS astronomy entries on 2022-09-14
author:"Bappu, M.K.V." OR author:"Vainu Bappu, M. K."
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Title: VizieR Online Data Catalog: Hydrogen-Line Absorption in
Early-Type Stars (Bappu+ 1962)
Authors: Bappu, M. K. V.; Chandra, S.; Sanwal, N. B.; Sinvhal, S. D.
1996yCat.2040....0B Altcode:
Photoelectric determinations of H-γ absorption line intensity have
been made of stars in selected clusters and associations as well as
in the general galactic field. Interference filters having a width at
half intensity of 45Å were used to isolate spectral regions centered
on 4280Å, H-γ and 4410Å. The Γ indices derived, which represent a
measure of H-γ absorption, can be used in conjunction with unreddened
values of either (U-B) or (B-V) for spectral and luminosity class
determinations of stars in the spectral range O6 to A0. <P />(1
data file).
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Title: Cosmic perspectives : essays dedicated to the memory of
M.K.V. Bappu
Authors: Bappu, M. K. V.; Biswas, S. K.; Mallik, D. C. V.;
Vishveshwara, C. V.
1989cped.book.....B Altcode: 1989QB51.C74.......
No abstract at ADS
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Title: A survey of red stars in the direction of the Large Magellanic
Cloud.III. Some regions north of the bar.
Authors: Bappu, M. K. V.; Parthasarathy, M.; Scaria, K. K.
1985KodOB...5....1B Altcode:
The authors have continued the survey for red stars in the direction of
the Large Magellanic Cloud using the technique of ultra-low dispersion
spectroscopy. In this paper they list 310 red stars located north of
the LMC bar. Finding charts and coordinates on the Hodge-Wright Atlas
Charts are provided.
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Title: REPORTS FROM ASTRONOMICAL CENTRES: Indian Institute of
Astrophysics
Authors: Bappu, M. K. V.
1984BASI...12..269B Altcode:
No abstract at ADS
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Title: REPORTS FROM ASTRONOMICAL CENTRES: Indian Institute of
Astrophysics
Authors: Bappu, M. K. V.
1984BASI...12..293B Altcode:
No abstract at ADS
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Title: Ca II emission in Canopus.
Authors: Bappu, M. K. V.; Mekkaden, M. V.; Kameswara Rao, N.
1984BASI...12...64B Altcode:
No abstract at ADS
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Title: CA II K emission in Canopus.
Authors: Bappu, M. K. V.; Mekkaden, M. V.; Rao, N. K.
1984BASI...12..196B Altcode: 1984BASI...12..196M
The changes in the Ca II K line profile of the F0 supergiant Canopus
have been studied from the high dispersion coude spectrograms obtained
since 1975. The emission in the core of the line is variable in a
timescale of few days. Similar activity seems to be occurring in Mg
II h and k lines also. This is attributed to the variability in the
appearance of plage areas on the stellar surface.
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Title: Distribution of Bhb-Stars in the Cluster Omega-Centauri and its
Effect on the Radial Change in Colour and Ellipticity of the Cluster
Authors: Scaria, K. K.; Bappu, M. K. V.
1984aprm.conf..449S Altcode:
The authors have studied the radial change in the distribution of giant
branch stars and the horizontal branch stars in ω Centauri. They
show how the observed change in the distribution is related to the
radial change in the colour of the cluster and also the radial change
in its ellipticity.
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Title: The absolute magnitudes of the Wolf-Rayet stars HD 151932
and HD 152270.
Authors: Shylaja, B. S.; Bappu, M. K. V.
1983KodOB...3..104S Altcode:
The absolute visual magnitudes of two Wolf-Rayet stars HD 151932 (WN
7) and HD 152270 (WC 7+O8) have been determined from their energy
distributions and monochromatic magnitudes least contaminated by
emission lines taking into account their membership with the open
cluster NGC 6231.
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Title: Understanding the Universe. The impact of space
astronomy. Based on talks given at the UN/IAU International Seminar on
the Occasion of UNISPACE 82, Hofburg, Vienna, Austria, 12 August 1982.
Authors: West, R. M.; Bappu, M. K. V.; Pal, Y.; Massevitch, A. G.
1983uuis.book.....W Altcode:
No abstract at ADS
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Title: Eclipse observations of coronal emission lines. I - Forbidden
Fe X 6374 A profiles at the eclipse of 16 February 1980
Authors: Singh, J.; Saxena, A. K.; Bappu, M. K. V.
1982JApA....3..249S Altcode:
Coronal spectra during the total solar eclipse of February 16,
1980, obtained in the 6374 A (forbidden Fe X) line using a multislit
spectrograph are discussed. The dispersion of these spectra is 2.5
A/mm. The observed line profiles from 1.1 to 1.7 earth radii, with
a spatial resolution of 10 x 22 sq arcsec, yield half-widths that
vary from 0.6 A to 2.4 A. A large number of locations are found to
have half-widths around 1.3 A, corresponding to a temperature of 4.6
x 10 to the 6th K. If temperatures of the order of 1.3 x 10 to the
6th K are typical of the regions that emit in the forbidden Fe X,
then turbulent velocities of approximately 30 km/s are required for
the enhanced line broadening. The line-of-sight velocities measured
are found to range from +14 km/sec to -17 km/sec. The velocities of
most of the locations are less than + or - 5 km/s. It is concluded
that the corona does not show any localized differential mass motion
and that it co-rotates with the photospheric layers deeper down.
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Title: Chromospheric activity of late-type giants and supergiants:
reappearance of dynamo activity in the interior due to the spin-up
of the core in evolution.
Authors: Uchida, Y.; Bappu, M. K. V.
1982JApA....3..277U Altcode:
The renewal of chromospheric activity in red giants and supergiants
is interpreted in terms of the reappearance of dynamo activity in the
interior due to the spin-up of the core caused by its contraction in
the course of evolution from the main sequence to the giant stage.
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Title: REPORTS FROM ASTRONOMICAL CENTRES: Indian Institute of
Astrophysics
Authors: Bappu, M. K. V.
1982BASI...10..165B Altcode:
No abstract at ADS
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Title: Membership of faint galactic clusters.
Authors: Bappu, M. K. V.; Babu, G. S. D.
1982BASI...10...41B Altcode:
No abstract at ADS
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Title: The sun is a star
Authors: Bappu, M. K. V.
1982sis..book.....B Altcode:
No abstract at ADS
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Title: Corrigendum
Authors: Scaria, K. K.; Bappu, M. K. V.
1981JApA....2....7S Altcode:
No abstract at ADS
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Title: Mass segregation in globular clusters
Authors: Scaria, K. K.; Bappu, M. K. V.
1981JApA....2..215S Altcode:
Photoelectric and photographic techniques are used to study the
color changes indicative of segregation effects over the cluster
omega-Cen and 47 Tuc. It is established that omega Cen is bluer
between 2 arcmin and 4 arcmin from the center, than anywhere else,
the B-I color difference between the center and this blue zone being
equal to about 0.45 mag. Equidensitometry of omega-Cen in B, V, and
infrared bands indicates a wavelength dependence, with the cluster
nearly spherical in the infrared band. The blue in this zone comes
from both a diffuse background of unresolved stars and an increase
in the relative abundance of horizontal branch stars. Results of
equidensitometry of the cluster 47 Tuc show that ellipticity is
increased with an increase in the blueness of the cluster, and is
dependent on the distance from the center. It is suggested that,
compared to the nearly spherical distribution of red stars in globular
clusters, blue stars form a bulge around the core with a more elliptical
distribution and a different orientation.
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Title: Presence of MG II emission in R CrB at maximum light.
Authors: Kameswara-Rao, N.; Nandy, K.; Bappu, M. K. V.
1981MNRAS.195P..71K Altcode: 1981MNRAS.195P..71R
The high dipersion spectrum of R CrB in the long wavelength obtained
near its maximum with the International Ultraviolet Explorer shows the
presence of chromospheric Mg II emission. For comparison the spectrum
of Gamma Cyg was obtained immediately afterwards. The Mg II emission
width of R CrB is found to be the same as that of Gamma Cyg.
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Title: REPORTS FROM ASTRONOMICAL CENTRES: Indian Institute of
Astrophysics
Authors: Bappu, M. K. V.
1981BASI....9..151B Altcode:
No abstract at ADS
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Title: Occultation of BD -19 4222 by Uranus
Authors: Bappu, M. K.; Liller, W.; Pande, M. C.; Mehra, H. S.; Pande
Vijaymohan, A. K.; Joshi, U. C.
1981IAUC.3599....2B Altcode:
M. K. Bappu, Indian Institute of Astrophysics; and W. Liller,
Harvard College Observatory, report that the Apr. 26 occultation
of BD -19 4222 by Uranus (cf. Klemola et al. 1981, A.J. 86, 138) was
successfully observed with the 0.8-m and 1.0-m reflectors at the Kavalur
Observatory. While scattered clouds hampered observations of the early
portion of the event, clearing skies permitted positive identification
of the epsillon-ring occultation at 20h38m37s UT and probably of several
other occultations also. M. C. Pande, Uttar Pradesh State Observatory,
reports that the occultation by Uranus was successfully observed at
Naini Tal by H. S. Mehra, A. K. Pande Vijaymohan and U. C. Joshi using
a 1.0-m reflector with EMI 9658 multiplier and a filter combination
having a peak response wavelength of 750 nm. The occultation lasted for
19.9 min centered at 19h54m.4 UT. Occultations by the epsillon ring
were recorded at 19h18m42s and 20h28m15s UT and were of durations 5s
and 3s, respectively.
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Title: A dependence on solar cycle of the size of the CA<SUP>+</SUP>
network
Authors: Singh, J.; Bappu, M. K. V.
1981SoPh...71..161S Altcode:
Calcium network diameters are shown to be smaller by 5% at solar
maximum than at minimum. The average cell size at minimum is 22
115 ± 99 km. The average size at solar maximum is 20 920 ± 112 km,
though individual maxima perform differently from each other depending
probably on the dispersed remnant magnetic fields. The change in size
of the network is interpreted in terms of changes in the size of the
supergranular convective cell.
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Title: Corrigendum - Mass Segregation in Globular Clusters
Authors: Scaria, K. K.; Bappu, M. K. V.
1981JApA....2..439S Altcode:
No abstract at ADS
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Title: New Research Journal - Journal of Astrophysics and Astronomy
Authors: Bappu, M. K. V.
1981S&T....61R.198B Altcode:
No abstract at ADS
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Title: Emission band and continuum photometry of Comet West
/1975n/. II Emission profiles of the neutral coma, lifetimes of
molecules and distribution of the molecules and dust within the coma
Authors: Bappu, M. K. V.; Parthasarathy, M.; Sivaraman, K. R.; Babu,
G. S. D.
1980MNRAS.192..641B Altcode:
The scale lengths of the CN and C2 molecules and their parents are
derived based on Haser's model from drift scans across the coma of Comet
West in the light of CN (0,0), C<SUB>2</SUB> (0,0) and the continuum
around 5000 Å. The analysis provides evidence to show that the CN
molecules are produced by the dissociation of two species of parent
molecules having entirely different lifetimes. A similar result is
also obtained for the C<SUB>2</SUB> molecules. <P />The step scans
of 1976 March 19.96, covering the spectral range 3700- 5300 Å and
at five independent locations inside the coma show that there is an
increase of reddening of the continuum, from the centre of the nucleus
outwards. These provide evidence that the coarser particles are to the
centre and the finer ones towards the periphery. A study of the radial
distribution of CN, C<SUB>3</SUB> and C<SUB>2</SUB> molecules and of
the dust particles shows that the C<SUB>3</SUB> (4050 Å) intensities
fall most rapidly, compared to CN or C<SUB>2</SUB>.
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Title: Preface
Authors: Bappu, M. K. V.
1980JApA....1....1B Altcode:
No abstract at ADS
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Title: Emission band and continuum photometry of Comet West /1975n/. I
- Heliocentric dependence of the flux in the emission bands and
the continuum
Authors: Sivaraman, K. R.; Babu, G. S. D.; Bappu, M. K. V.;
Parthasarathy, M.
1979MNRAS.189..897S Altcode:
Spectrum scans of the coma of Comet West (1975n) covering the range
λλ3700--5700 Å were made on eight nights when the heliocentric
distance of the comet varied from 0.588 to 0.853 AU. These have been
used to derive the absolute flux in the CN(0,0), C<SUB>3</SUB>(4050),
C<SUB>2</SUB>(1, 0) and C<SUB>2</SUB>(0, 0) bands as well as in the
continuum. Enhancements in the band emissions were noticed on three
nights in CN(0,0), C<SUB>3</SUB>(4050) and C<SUB>2</SUB>(1, 0). The
column densities of neutral sodium atoms are derived from scans around
5900 Å on four nights. The column densities of CO<SUP>+</SUP> ions
corresponding to four prominent band sequences are evaluated from two
scans of the tail.
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Title: Extended Ring System of Uranus
Authors: Bhattacharyya, J. C.; Bappu, M. K. V.; Mohin, S.; Mahra,
H. S.; Gupta, S. K.
1979M&P....21..393B Altcode:
Two photoelectric records of the occultation event on 10 March, 1977,
obtained by two 102-cm-aperture telescopes, spaced 1500 km apart,
are critically analysed and indications of a complex structure
of distribution of occulting material surrounding the planet are
obtained. The results confirm the existence of a very shallow broad
ring system with local condensation lanes of narrow and intermediate
widths. A system of numerous thin rings are also present around the
planet in the equatorial plane.
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Title: Radiation and Structure of the Solar Atmosphere
Authors: Bappu, M. K. V.
1979IAUTA..17b..49B Altcode: 1979IAUT...17...49B
No abstract at ADS
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Title: Emission band and continuum photometry of comet West (1975n).
Authors: Babu, G. S. D.; Bappu, M. K. V.; Parthasarathy, M.; Sivaraman,
K. R.
1978BASI....6R..51B Altcode:
No abstract at ADS
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Title: Violet absorption edges of C IV lines in Wolf-Rayet spectra:
possible superposition with diffuse interstellar bands at 5780 Å
and 5797 Å.
Authors: Giridhar, S.; Bappu, M. K. V.
1978KodOB...2..161G Altcode:
No abstract at ADS
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Title: On some photographic aids for the measurement of astronomical
spectra
Authors: Bappu, M. K. V.
1978mtap.conf..263B Altcode:
No abstract at ADS
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Title: A survey of red stars in the direction of the Large Magellanic
Cloud. 2. Some regions around the bar.
Authors: Bappu, M. K. V.; Parthasarathy, M.; Scaria, K. K.
1978KodOB...2..184B Altcode:
No abstract at ADS
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Title: The astronomical seeing at Kavalur.
Authors: Bappu, M. K. V.; Mohin, S.; Unnikrishnan, K. G.
1978KodOB...2..168B Altcode:
No abstract at ADS
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Title: Saturn-like ring system around Uranus
Authors: Bhattacharyya, J. C.; Bappu, M. K. V.
1977Natur.270..503B Altcode:
OBSERVATIONS made at Kavalur<SUP>1,2</SUP> of the occultation of
SAO158687 by Uranus on 10 March 1977 showed, in addition to the
occultation by a satellite system termed the ɛ ring, a dimming of the
light of the star close to the time when the atmosphere of the planet
could have caused the phenomenon. Since then, the identities of the α,
β, γ, δ rings have also become well established, and a theoretical
interpretation of their origin<SUP>3</SUP> has been proposed. We have
closely examined the Kavalur photoelectric record and describe here
several new features of the satellite ring system of Uranus.
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Title: Indian Institute of Astrophysics. Report for the year 1975
April 1 to 1976 March 31.
Authors: Bappu, M. K. V.
1977QJRAS..18..396B Altcode:
No abstract at ADS
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Title: Prominences
Authors: Bappu, M. K. V.
1977QJRAS..18..286B Altcode:
No abstract at ADS
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Title: Possible Occultations by Uranian Rings
Authors: McCrosky, R. E.; Klemola, A. R.; Shao, C. -Y.; Marsden,
B. G.; Elliot, J. L.; Kozai, Y.; Tomita, K.; Bappu, M. K. V.
1977IAUC.3068....1M Altcode:
R. E. McCrosky, Center for Astrophysics, has pointed out that two stars
of magnitude 11-12 come close to being occulted by the Uranian rings
at the end of May. A. R. Klemola, Lick Observatory, has measured the
accurate positions of the stars on a recent plate taken with the 51-cm
double astrograph, and he confirms that no other stars of magnitude ~
14 or brighter will be within some 10" of the center of Uranus during
the next three months. These positions have mean errors of perhaps
+/- 0".2 and were reduced to the FK4 system with the help of 34 SRS
positions (kindly telexed by L. Kohoutek, Hamburg Observatory) from
the new Perth 70 star catalogue. The indicated near-occultation times,
star positions, and also approximate magnitudes and spectral types
(the latter derived by C.-Y. Shao from the Palomar Sky Survey prints)
are as follows: 1977 UT Star R.A. (1950) Decl. Mag. Sp. May 29.99 AC
1420-13:127 14 23 52.79 -13 48 36.4 12 A 31.27 AC 1420-13:123 14 23
42.42 -13 47 46.5 11.5 F Computations by B. G. Marsden suggest that the
stars, which have their closest approaches to Uranus in p.a. 18o, will
not be occulted by the epsilon ring (radius 4".0); but as J. L. Elliot,
Cornell University, has pointed out, there could be as yet undetected
rings up to ~ 5" from Uranus. Local circumstances for the minimum
separations are: Location UT Sep. UT Sep. Sutherland May 29d23h48m 5"6 -
- Herstmonceux 29 23 52 6.2 - - La Plata 29 23 53 5.5 May 31d06h35m 5"8
La Serena 29 23 54 5.5 31 06 35 5.9 Tucson - - 31 06 39 6.3 Wellington -
- 31 06 41 5.6 South Pole 29 23 50 5.3 31 06 38 5.5 Y. Kozai, Tokyo
Astronomical Observatory, has communicated a photometric tracing
recorded by K. Tomita at the Dodaira Station during the period of ring
occultations of SAO 158687 on Mar. 10. Unfortunately, the epsilon
occultation seems to have occurred during a 0.8-min interruption to
observe the sky background. M. K. V. Bappu writes that the times of
the Kavalur observations (IAUC 3061; IAUC 3051 for epsilon) should be
changed by -3s.
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Title: Occultation of SAO 158687 by Uranian Rings
Authors: Sinvhal, S. D.; Mahra, H. S.; Gupta, S. K.; Bappu, M. K. V.;
Marsden, B. G.
1977IAUC.3061....1S Altcode:
S. D. Sinvhal, Uttar Pradesh State Observatory, reports that four
secondary occultations of SAO 158687 on Mar. 10 were observed by
H. S. Mahra and S. K. Gupta with the 104-cm reflector at Naini Tal as
shown below. The occultations can be identified with those of Elliot et
al. (IAUC 3051) and are therefore denoted accordingly: Event UT Duration
Event UT Duration alpha1 20h32m01s 1s gamma1 20h27m19s 1s beta1 20 30
25 1 delta1 20 26 15 1 The observations extended from 20h22m10s (i.e.,
after the epsilon occultation occurred) to 21h30m UT with a break during
20h27m55s-20h28m40s. M. K. V. Bappu, Indian Institute of Astrophysics,
reports that further examination of the Kavalur tracing (cf. IAUC 3048,
3051, 3058) reveals further occultations. He specifies the times with
reference to the middle of the epsilon5 event. The analysis below
suggests that the time for epsilon5 given on IAUC 3051 is most likely
to be correct, so the times for the other occultations become: Event UT
Event UT alpha1 20h30m14s gamma1 20h25m44s beta 20 28 43 delta1 20 24 44
On the assumption that the Elliot-et-al. alpha, beta, gamma and delta
rings are circular, centered on Uranus and in its equatorial plane,
a least-squares adjustment by B. G. Marsden using the 25 available
observations (see also IAUC 3051, 3058) yields the radii (in km and with
individual mean errors) listed below. The radii corresponding to the
other reported rings (using the midtimes specified for the occultations)
are also given: Ring Distance Ring Distance alpha3 42 550 delta 48
510 +/- 30 beta3 42 810 epsilon1,3,5 51 790 +/- 10 alpha 44 950 +/-
40 epsilon2,4 51 120 +/- 10 beta 45 890 +/- 30 zeta4 53 720 gamma 47
840 +/- 20 If the time given for epsilon5 on IAUC 3058 is adopted, the
distances corresponding to the Kavalur occultations are all increased
by ~ 150 km. The western (odd subscripts) and eastern (even subscripts)
sections of epsilon show that this ring is significantly asymmetric,
but although the p.a. at Uranus of the epsilon1 and epsilon2 events
differs by 110o, that of the epsilon1 and epsilon2 events differs by
as much as 8o. With the Uranus-occultation duration of 25 (+/- 0.5)
min given by Elliot et al. for the Airborne Observatory (IAUC 3048)
the radius of Uranus (assumed to have circular cross-section) is 26
450 +/- 70 km.
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Title: Occultation of SAO 158687 by Uranian Satellite Belt
Authors: Elliot, J. L.; Dunham, E.; Mink, D.; Millis, R. L.; Birch, P.;
Trout, D.; Feast, M. W.; Churms, J.; Bappu, M. K. V.; Marsden, B. G.
1977IAUC.3051....1E Altcode:
J. L. Elliot, E. Dunham and D. Mink, Cornell University, report that
their observations from the Kuiper Airborne Observatory show a group
of five secondary occultations of SAO 158687 both before and after
the star was occulted by Uranus on Mar. 10 (cf. IAUC 3048). They
note that the times of the individual secondary occultations are
remarkably symmetrical with respect to the occultation by Uranus
itself and suggest that the occulting material is therefore confined
to specific narrow rings in the 7000-km-wide belt. The events, labeled
with Greek letters in order of increasing separation from Uranus, were
recorded as follows, where the UT times correspond to the middle of each
occultation, and the subscripts 1 and 2 refer to the different (mean)
locations of the Airborne Observatory (the altitude of which was 12.5
km), namely, 1: Long. = -82o11', Lat. = -50o20'; 2: Long. = -101o19',
Lat. = -50o21'. Event UT Duration Event UT Duration alpha1 20h20m55s
1s alpha2 21h45m52s 1s beta1 20 19 34 1 beta2 21 47 06 1 gamma1 20 16
58 1 gamma2 21 49 45 1 delta1 20 16 03 1 delta2 21 50 39 1 epsilon1 20
11 46 7 epsilon2 21 54 06 4 R. L. Millis, Lowell Observatory, reports
that five occultation events were also detected by P. Birch, D. Trout
and himself with the 61-cm reflector at the Perth Observatory (cf. IAUC
3048). Mid-times of these events (denoted with subscript 3) are: Event
UT Duration Event UT Duration alpha3 20h23m43s 1s delta3 20h15m59s 1s
beta3 20 23 19 1 epsilon3 20 10 33 8 gamma3 20 18 44 1-2 M. W. Feast,
South African Astronomical Observatory, reports that J. Churms monitored
the occultation at Cape Town (subscript 4) and (after learning of the
times observed by Elliot et al.) provided the following mid-times for
some short-duration events: Event UT Duration Event UT Duration alpha4
21h55m20s - delta4 22h00m13s _ beta4 21 56 38 - epsilon4 22 03 44 6s
gamma4 21 59 18 - zeta4 22 07 11 8 These first four events were the
only ones of significance (dips of ~ 1 mm on the photometer trace)
observed between 21h45m and 22h02m UT. Observations began at 20h40m,
but the trace was less steady during the early stages because of low
altitude. The epsilon4 event was a major one (amounting to ~ 1 cm on the
trace, about as much as the Uranus occultation itself), and the trace
was noticeably ragged (dips ~ 1 mm) between 22h02m and 22h05m. The
zeta4 occultation had a depth of 3 mm but occurred at the very end
of the trace. Feast remarks that the photometer was a conventional
(not a high speed) one and that the dips of short duration will not
be faithfully reproduced as to their shape. A letter received from
M. K. V. Bappu, Indian Institute of Astrophysics, gives the time of
the beginning of the occultation observed at Kavalur as 20h19m51s UT
(rather than 20h19m15s; cf. IAUC 3048), from which we can define for
the middle of the event: Event UT Duration epsilon5 20h19m55s 9s The
values correlated below for the distances of the occulting material
from the center of Uranus (in km, and projected on the plane of Uranus'
equator) were derived by the undersigned. The relative positions of
Uranus and the star were adjusted so that the distances for the first
four events with subscripts 1 and 2 coincide (the mutual agreement
among them being +/- 40 km) and so that the distance for epsilon5 is
the mean of those for epsilon1 and 2 (i.e. 51 700 km). Coincidence of
the distances for epsilon5 and 1 produces an increase of ~ 600-700 km in
the distances of the rings. Event Distance Event Distance Event Distance
alpha3 42 200 beta3 42 500 alpha1,2 44 900 alpha4 45 000 beta1,2 45
900 gamma3 45 700 beta4 46 000 gamma1,2 47 900 delta3 47 800 gamma4
48 000 delta1,2 48 600 delta4 48 800 epsilon1 52 000 epsilon3 51 900
epsilon2 51 400 epsilon4 51 600 epsilon5 54 300 Dr. Elliot is planning
to make a detailed study of these occultations and would appreciate
receiving observations (including photometer tracings). His address
is: Center for Radiophysics and Space Research, Cornell University,
Ithaca, NY 14853, U.S.A.
---------------------------------------------------------
Title: Occultation of SAO 158687 by Uranus and Satellite Belt
Authors: Elliot, J. L.; Dunham, E.; Mink, D.; Millis, R. L.; Birch,
P.; Trout, D.; Bappu, M. K. V.; Bhattacharyya, J. C.; Kuppuswamy;
Marsden, B. G.
1977IAUC.3048....1E Altcode:
Amplifying the brief announcement on IAUC 3047, J. L. Elliot reports
that several secondary occultations of SAO 158687 on Mar. 10 were
observed by E. Dunham, D. Mink and himself from the Kuiper Airborne
Observatory and also by R. L. Millis, P. Birch and D. Trout at the Perth
Observatory. Both groups independently concluded that these occultations
were caused by bodies that are apparently part of a satellite belt
about 40 000 km distant from the center of Uranus. The diameters of the
satellites range from 100 km to much smaller values. The occultation by
Uranus itself was successfully observed from the Airborne Observatory
(located at Long. = -90o, Lat. = -50o) and lasted ~ 25 min centered
on 21h06m UT. The Uranus occultation did not occur at the Perth
Observatory. The secondary occultations took place during an 8-9
min interval around 20h16m UT and during a similar interval around
21h50m UT (although dawn prevented observations of the latter events
in Perth). M. K. V. Bappu, Indian Institute of Astrophysics, cables:
"Using the 102-cm reflector at Kavalur (Long. = -5h15m19s.6, Lat. =
+12o34'32"), Bhattacharyya and Kuppuswamy found the diminution of
SAO 158687 during the occultation by the atmosphere of Uranus to be
0.046 magnitude at an effective wavelength of 7500 A. Visually and
photoelectrically they observed the complete disappearance of the star
for 8s.9 beginning at 20h19m15s UT and ascribe this to obscuration
by a hitherto unknown satellite of the planet." Computations by the
undersigned show that the asymmetry in the times of the satellite
occultations about the main occultation (as observed at the Airborne
Observatory) is consistent with the existence of a circular belt in
the plane of Uranus' equator. Allowance for foreshortening yields the
radii of the inner and outer edges of the belt as 44 000 and 51 000
km, respectively. The Kavalur observation suggests occultation by a
100-km-sized body near the outer edge of the belt. Other observers are
urged to examine their records for further evidence of this belt. At
Sutherland, times of mid-occultation by the belt would have been
20h22m and 21h59m UT; at Mauritius, 20h23m and 21h54m; at Lembang,
20h20m and 21h46m; at Kyoto, 20h22m; at Helwan, 21h56m. Those wishing
to attempt to detect the satellite belt directly are advised that at
the present opposition it should be located from 3".5 to 4".0 to the
north and south of the center of Uranus and from 2".7 to 3".1 to the
east and west; the brightest bodies in it are expected to have mv ~ 19.
---------------------------------------------------------
Title: K emission line widths in the Sun and the stars.
Authors: Bappu, M. K. V.; Sivaraman, K. R.
1977MNRAS.178..279B Altcode:
K-emission line widths measured with a micrometer on integrated spectra
of the sun have a mean value of 38.2 km/s. A definition is proposed
whereby the width is a measure in km/s at the inverse-e value of the
difference between the intensity of the brighter K2 peak over the
K1 background, reckoned from this latter level. Averaged spectra over
different parts of the solar disk show the very appreciable contribution
by rotation to the emission line width, making it imperative for any
calibration of width with absolute magnitude to use a solar value
derived from an integrated spectrum. Arguments are presented showing
that the K-emission profile observed in other stars is the profile
of the typical bright mottle that should enable the derivation of
chromospheric parameters. From measures of Doppler displacements of
both K2 and K3, 'dark condensations' as seen on the sun play a role
in the atmospheres of stars with K emission.
---------------------------------------------------------
Title: Ultra-low dispersion spectroscopy of stars and galaxies.
Authors: Bappu, M. K. V.; Parthasarathy, M.
1977KodOB...2....1B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: A survey of red stars in the direction of the Large Magellanic
Cloud. 1. The 30 Doradus region.
Authors: Bappu, M. K. V.; Parthasarathy, M.; Scaria, K. K.
1977KodOB...2...85B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: An automated spectrum scanner.
Authors: Bappu, M. K. V.
1977KodOB...2...64B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The Wolf-Rayet spectroscopic binary HD 214419.
Authors: Bappu, M. K. V.; Visvanadham, P.
1977KodOB...2...89B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The near-infrared spectra of Wolf-Rayet stars.
Authors: Bappu, M. K. V.; Ganesh, K. S.; Scaria, K. K.
1977KodOB...2...28B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Indian Institute of Astrophysics.
Authors: Bappu, M. K. V.
1976QJRAS..17..341B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Prominences
Authors: Bappu, M. K. V.
1976QJRAS..17...63B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Radiation and structure of the solar atmosphere (Radiation
et structure de l'atmosphère solaire).
Authors: Giovanelli, R. G.; Mein, P.; Bappu, M. K. V.; Jordan, C.;
MacQueen, R. M.
1976IAUTA..16b..55G Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Indian Institute of Astrophysics. Report for the year 1973
April 1 to 1974 March 31.
Authors: Bappu, M. K. V.
1975QJRAS..16..184B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Prominences
Authors: Bappu, M. K. V.
1975QJRAS..16...38B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Book reviews
Authors: van de Stadt, Herman; Rawer, Karl; Schadee, A.; Noyes, R. W.;
Bleeker, J. A. M.; Wittenberg, H.; de Graaff, W.; Akasofu, S. -I.;
Hooykaas, R.; Bappu, M. K. V.; Atanasijević, I.; Icke, Vincent;
van der Valk, F.; Kresàk, L.; Müller, Edith A.
1975SSRv...17..159V Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Photelectric spectrophotometry of early type stars.
Authors: Bappu, M. K. V.; Nandy, K.; Parthasarathy, M.; Rajamohan, R.
1975BASI....3Q..30B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Research with a moderate aperture telescope.
Authors: Bappu, M. K. V.
1975oams.conf...35B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Indian Institute of Astrophysics. Report for the year 1972
April 1 to 1973 March 31.
Authors: Bappu, M. K. V.
1974QJRAS..15..302B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: On detection of QSOs by ultra low dispersion spectroscopy.
Authors: Bappu, M. K. V.; Parthasarathy, M.
1974BASI....2...36B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Presidential Address
Authors: Bappu, M. K. V.
1974BASI....2...23B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Sodium emission in comet Kohoutek (1973f).
Authors: Bappu, M. K. V.; Parthasarathy, M.; Sivaraman, K. R.
1974BASI....2R..35B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The current shell spectrum of Pleione.
Authors: Prabhu, T.; Bappu, M. K. V.
1974BASI....2Q..36P Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Infrared and millimeter range astronomy. Proceedings of a
seminar held at Hyderabad, India, 25_-_26 Februar 1974.
Authors: Alladin, S. M.; Abhyankar, K. D.; Bappu, M. K. V.
1974imra.conf.....A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Elliptical galaxies with compact nuclei.
Authors: Bappu, M. K. V.; Parthasarathy, M.
1974BASI....2R..37B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Solar Prominences in 1972
Authors: Bappu, M. K. V.
1973QJRAS..14..407B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Indian Institute of Astrophysics. Report for the year 1971
April 1 to 1972 March 31.
Authors: Bappu, M. K. V.
1973QJRAS..14..209B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Comet Kohoutek (1973f).
Authors: Bappu, M. K. V.; Parthasarathy, M.; Sivaraman, K. R.;
Matchett, V. L.; Mayo, M.; Truxton, J.; Sherrod, C.
1973IAUC.2608....1B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: On the K-Line Width-Absolute Magnitude Relation
Authors: Bappu, M. K. V.
1973IAUS...54...64B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Wolf-Rayet and high-temperature stars proceedings from IAU
Symposium no. 49 held in Buenos Aires, Argentina, August 9-14, 1971.
Authors: Bappu, M. K. V.; Sahade, Jorge
1973IAUS...49.....B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Photometry of the solar corona of March 7, 1970.
Authors: Bappu, M. K. V.; Bhattacharyya, J. C.; Sivaraman, K. R.
1973Prama...1..117B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The Spectra of Wolf-Rayet Stars at High Dispersion
Authors: Bappu, M. K. V.
1973IAUS...49...59B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Solar Prominences in 1971
Authors: Bappu, M. K. V.
1972QJRAS..13..525B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: On Emission Lines of Hydrogen, Helium and Ionized Calcium
Seen on a Coronal Spectrogram of the March 7, 1970 Eclipse
Authors: Bappu, M. K. V.; Bhattacharyya, J. C.; Sivaraman, K. R.
1972SoPh...26..366B Altcode:
Emission lines of the Balmer series, D<SUB>3</SUB> and H and K are
reported present on a coronal spectrogram obtained at the March 7,
1970 eclipse. Arguments are presented to show that these could not
have originated from scattering in the Earth's atmosphere and hence
possibly have a coronal origin.
---------------------------------------------------------
Title: Kodaikanal Observatory, Kodaikanal. Report for the period
January 1970 to March 31, 1971.
Authors: Bappu, M. K. V.
1972QJRAS..13..448B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Solar Prominences in 1970
Authors: Bappu, M. K. V.
1972QJRAS..13...70B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Annual report of the Kodaikanal Observatory for the year 1969.
Authors: Bappu, M. K. V.
1972arko.book.....B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Optical astronomy in India - prospects of the next decade.
Authors: Bappu, M. K. V.
1972CSci...41..829B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: K Emission-Line Widths and the Solar Chromosphere
Authors: Bappu, M. K. V.; Sivaraman, K. R.
1971SoPh...17..316B Altcode:
Closely spaced microphotometer tracings parallel to the dispersion of
one excellent frame of a K-line time sequence have been utilized for a
study of the nature of the K<SUB>2v</SUB>, K<SUB>2R</SUB> intensities
in the case of the solar chromosphere. The frequency of occurrence
of the categories of intensity ratio are as follows: per cent; per
cent; per cent; per cent; per cent. Two types of absorbing components
are postulated to explain the pattern of observed K<SUB>2v</SUB>,
k<SUB>2R</SUB> intensity ratios. One component with minor Doppler
displacements acting on the normal K<SUB>232</SUB> profile, where
K<SUB>2V</SUB> >K<SUB>2R</SUB>, produces the cases K<SUB>2v</SUB>
≫ K<SUB>2R</SUB>, K<SUB>2v</SUB> = K<SUB>2R</SUB>, K<SUB>2v</SUB>
<K<SUB>2R</SUB>. The other component arises from `dark condensations'
which are of size 3500 kms as seen in K<SUB>2R</SUB>. They have
principally large down flowing velocities in the range 5-8 km/sec and
are seen on K<SUB>3</SUB> spectroheliograms with sizes of about 5000
kms, within the coarse network of emission. These `dark condensations'
give rise to the situation K<SUB>2R</SUB> = 0.
---------------------------------------------------------
Title: Summary of magnetic and ionospheric observations, January -
June, 1968.
Authors: Bappu, M. K. V.
1971KodOB.201....1B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Summary of magnetic and ionospheric observations, July -
December, 1967.
Authors: Bappu, M. K. V.
1971KodOB.199..915B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Summary of solar observations for the second half of 1969.
Authors: Bappu, M. K. V.
1971KodOB.207..169B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Summary of magnetic and ionospheric observations, January -
June 1966.
Authors: Bappu, M. K. V.
1971KodOB.194.....B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Summary of solar observations for the first half of 1969.
Authors: Bappu, M. K. V.
1971KodOB.206..141B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Solar activity.
Authors: Laurie, P. S.; Bappu, M. K. V.
1970QJRAS..11..219L Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Kodaikanal Observatory, Kodaikanal. Report for the year ending
1969 December 31.
Authors: Bappu, M. K. V.
1970QJRAS..11..366B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Summary of prominence and calcium flocculus observations,
magnetic observations, and ionospheric observations for the first
half of 1964.
Authors: Bappu, M. K. V.
1970KodOB.174.....B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Summary of prominence and calcium flocculus observations,
magnetic data, and ionospheric data for the second half of 1964.
Authors: Bappu, M. K. V.
1970KodOB.175.....B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Summary of prominence and calcium flocculus observations,
magnetic data, ionospheric data, for the second half of 1969.
Authors: Bappu, M. K. V.
1970KodOB.177.....B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Summary of solar observations, January - December 1967.
Authors: Bappu, M. K. V.
1970KodOB.196...41B Altcode: 1970KodOB.196..41.B
No abstract at ADS
---------------------------------------------------------
Title: Summary of prominence and calcium flocculus observations,
magnetic data, and ionospheric data for the first half of 1965.
Authors: Bappu, M. K. V.
1970KodOB.176.....B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Annual report of the Kodaikanal Observatory for the year 1968.
Authors: Bappu, M. K. V.
1970arko.book.....B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Summary of solar observations, January - June, 1966.
Authors: Bappu, M. K. V.
1970KodOB.192.....B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Summary of magnetic and ionospheric observations January -
June, 1967.
Authors: Bappu, M. K. V.
1970KodOB.198.....B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Kodaikanal Observatory, Kodaikanal. Report for the year ending
1968 December 31.
Authors: Bappu, M. K. V.
1969QJRAS..10..317B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Some characteristics of the solar wind inferred from the
study of sodium emission from cometary nuclei
Authors: Bappu, M. K. V.; Sivaraman, K. R.
1969SoPh...10..496B Altcode:
Seventeen comets, having information on sodium D-line emission during
their apparition, have been studied. The heliocentric distances
corresponding to the sodium emission commencement or termination epoch
are found to have a dependence on the phase of the solar cycle. For
comets appearing during a solar maximum the sodium emission is
detectable out to greater distances than, for the comets appearing
during solar minimum. The sodium emission is also found to depend on
heliographic latitude of the comet. It is concluded that the spatial
properties of the solar wind during a solar maximum and minimum are
responsible for the observed dependence.
---------------------------------------------------------
Title: Reports on the progress of astronomy: Solar activity (sunspots,
prominences).
Authors: Laurie, P. S.; Bappu, M. K. V.
1969QJRAS..10..239L Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Kodaikanal Observatory. Report for the year ending 1967
December 31.
Authors: Bappu, M. K. V.
1969QJRAS..10...60B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Comet Ikeya-Seki (1965) and the nature of the interplanetary
medium during its apparition.
Authors: Bappu, M. K. V.; Sivaraman, K. R.
1969KodOB.187.....B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Quasars - Observational
Authors: Bappu, M. K. V.
1969crsr.conf..217B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The solar corona of July 20, 1963.
Authors: Bappu, M. K. V.; Bhatnagar, A.
1969KodOB.190.....B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: An analysis of the cepheid variable RT Aurigae
Authors: Bappu, M. K. V.; Raghavan, Nirupama
1969MNRAS.142..295B Altcode:
High dispersion spectra of the cepheid variable RT Aurigae have been
used for an analysis of the parameters of the stellar atmosphere over
a cycle of pulsation. Eighteen of these spectra were utilized for a
study of the radial velocities. The displacement curve derived from
the velocities was utilized with the light and colour curves of Eggen,
Gascoigne & Burr to furnish by the application of Wesselink's
method, a value of RIR o = 33.7. A differential curve of growth analysis
relative to the Sun has been carried out at eleven phases to evaluate
the variation of the atmospheric parameters. The range in Oexe is from
to . The variation of K is by a factor of ten over the cycle. A second
hump in this curve at phase P is perhaps a result of the sudden onset
of a pulse of compression. Mean abundances relative to [Fe] have been
derived for 21 elements. A general deficiency in s-process elements
is seen in comparison with those formed by the e-process.
---------------------------------------------------------
Title: Summary of prominence and calcium flocculus observations,
magnetic data, and ionospheric data for the second half of 1963.
Authors: Bappu, M. K. V.
1969KodOB.173.....B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Summary of prominence and calcium flocculus observations,
magnetic data, and ionospheric data for the first half of 1963.
Authors: Bappu, M. K. V.
1969KodOB.171.....B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Summary of solar observations for the second half of 1968.
Authors: Bappu, M. K. V.
1969KodOB.203B.115B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Stellar chromospheres.
Authors: Bappu, M. K. V.
1969KodRe..37.....B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Annual report of the Kodaikanal Observatory for the year 1967.
Authors: Bappu, M. K. V.
1969arko.book.....B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: On the Development of Magnetic Fields in Active Regions
Authors: Bappu, M. K. V.; Grigorjev, V. M.; Stepanov, V. E.
1968SoPh....4..409B Altcode:
Transverse and longitudinal magnetic field scans together with
K<SUB>232</SUB> spectroheliograms that cover the early phases of
active region formation reveal the following: The new active region
forms near the periphery of an old magnetic region. There is evidence
that the new region forms an interrelated system with the old magnetic
structures on the sun.
---------------------------------------------------------
Title: Summary of prominence observations, magnetic observations,
and ionospheric observations for the second half of 1962.
Authors: Bappu, M. K. V.
1968KodOB.169.....B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Chromospheric Heights in Active Regions
Authors: Bappu, M. K. V.; Sivaraman, K. R.
1968IAUS...35..247B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Summary of prominence and calcium flocculus observations,
magnetic observations, and ionospheric observations for the first
half of 1962.
Authors: Bappu, M. K. V.
1968KodOB.168.....B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Annual report of the Kodaikanal Observatory for the year 1966.
Authors: Bappu, M. K. V.
1968arko.book.....B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Excitation temperatures of the Wolf-Rayet stars
Authors: Bappu, M. K. V.; Chitre, S. M.
1968MNRAS.140...71B Altcode:
Hydrogenic transitions of C iv are used to derive excitation
temperatures for WoIf-Rayet stars of the WC sequence. The line
intensities of such transitions in HD 165763, HD 192641, HD 192103
and HD 184738 are derived from measures of equivalent widths on
spectra of 10 A/mm and 20 A/mm dispersion. These intensities are
corrected for continuum values derived by the method of photoelectric
spectrophotometry. This technique of temperature determination yields
values of temperature unaffected by non-LTE effects in the Wolf-Rayet
atmosphere. The mean values obtained are as follows: HD 165763
(WC6) 569000*26000; HD 192641 (WC7) 516000*63000; HD 192103 (WC7)
373000*34000; HD 184738 (WC8) 240000*4I000K. The intensities of the (4n)
series of He ii are used to derive an excitation temperature of the WN7
star HD 192163, using intensities measured on a single high dispersion
Mount Wilson coude' spectrogram. The value derived is 32 4000+42000. A
Balmer contribution to the emission of the Pickering series is obvious,
though the hydrogen emission present is little. Arguments are presented
to show that the (5 ) transition 8236 A and the (5-15) transition 6406
A can be utilized on high dispersion spectra for obtaining reliable
excitation temperatures of stars of the WN sequence.
---------------------------------------------------------
Title: Monochromatic polarization measures of comet Ikeya-Seki (1965f)
Authors: Bappu, M. K. V.; Sivaraman, K. R.; Bhatnagar, A.; Natarajan,
V.
1967MNRAS.136...19B Altcode:
Monochromatic measures of polarization of Comet Ikeya-Seki (I 965f)
at 3 890 A, 4 300 A, 4 740 A and 5 875 A are described. The relative
contributions of emission and continuum to radiation transmitted by
the fflters at 3 890 A and 4740 A are evaluated. The polarization
at phase angle 900 of the CN (o,o) band is 6'9% while that of the C2
(1,0) band is %, in close agreement with the theoretical values for
resonance fluorescence. The polarization value of the continuum is
% at phase angle 900, while for the same phase angle, a measure of
the polarization in the tail, 3' away from the head, is 13' 6%. The
agencies responsible for the continuum in both head and tail are likely
to have a difference in the major constituent. The role of ices and
iron particles as scattering agencies is discussed. -
---------------------------------------------------------
Title: Solar Physics at Kodaikanal
Authors: Bappu, M. K. V.
1967SoPh....1..151B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Emission band photometry of comet Ikeya-Seki (1965f)
Authors: Bappu, M. K. V.; Sivaraman, K. R.
1967MNRAS.137..151B Altcode:
Photoelectric measures of emission band intensities of C2 (I, o) and
CN (o, o) of the coma of Comet Ikeya-Seki (1965f) are reported. The
measured fluxes are utilized to determine the number of molecules of
C2 and CN that contribute to the observed emission.
---------------------------------------------------------
Title: Reports on the Progress of Astronomy: Solar
Activity-Prominences
Authors: Vainu Bappu, M. K.
1965QJRAS...6..335V Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Photoelectric observations of the 1963-1964 eclipse of
zeta Aurigae
Authors: Bappu, M. K. V.; Doss, A. T.; Viswanadham, P.
1965Obs....85...85B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Solar Activity-Prominences
Authors: Vainu Bappu, M. K.
1964QJRAS...5..227V Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Solar Activity-Prominences
Authors: Vainu Bappu, M. K.
1963QJRAS...4..301V Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The influence of superflares in the H alpha striation pattern
Authors: Bappu, M. K. V.; Bhatnagar, A.; Punetha, L. M.
1962Obs....82..192B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Calcium faculae and solar flare effects
Authors: Bappu, M. K. V.; Punetha, L. M.
1962Obs....82..170B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Photoeletric measures of hydrogen-line absorption in early-type
stars.
Authors: Bappu, M. K. V.; Chandra, S.; Sanwal, N. B.; Sinvhal, S. D.
1962MNRAS.123..521B Altcode:
Photoelectric determinations of H absorption line intensity have been
made of stars in selected clusters and associations as well as in the
general galactic field. Interference filters having a width at half
intensity of 45 A were used to isolate spectral regions centred on
4z80 A, H and 4410 A. The F indices derived, which represent a measure
of the Hy absorption, can be used in conjunction with unreddened
values of either (U-B) or (B - V) for spectral and luininosity class
determinations of stars in the spectral range O6 to Ao. The separation
of age loci is shown to exist on F, (U-B)0 diagrams of clusters and
associations having different ages. A F, Mv calibration for the young,
or less evolved stars, has been derived. Tests of such a calibration
have been made on the Orion Association and NGC z362. The distance
moduli thus obtained are in good agreement with the values derived
from the colour magnitude arrays.
---------------------------------------------------------
Title: Polarization measures of Comet Arend-Roland (1956h) and Comet
Mrkos (1957d).
Authors: Vainu Bappu, M. K.; Sinvhal, S. D.
1960MNRAS.120..152V Altcode:
Measurements of polarization of Comet Arend-Roland and of Comet Mrkbs
made photoelectrically, using interference filters and conventional B,
V filters are given. The interference filters were chosen to isolate
the Na emission at 5890 A and the continuum at 4800 A and 4300 A. The
polarization at 4800 A in both comets is similar yielding a mean value
of 20 1 per cent computed for a phase angle of 900. This indicates
that the agencies responsible for the continuum were identical in both
comets. The polarization of Na emission calculated for a phase angle
of 900 for Comet Mrkos was per cent in agreement with the theoretical
value for Na resonance radiation.
---------------------------------------------------------
Title: Report of proceedings of Uttar Pradesh State Observatory,
Naini Tal
Authors: Bappu, M. K. V.
1959MNRAS.119..399B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Interference filter photometry of weak emission lines in
CQ Cephei
Authors: Bappu, M. K. V.; Sinvhal, S. D.
1959Obs....79..140B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The light variation of 6 Cassiopeiae
Authors: Bappu, M. K. V.
1959Obs....79..100B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: 3. A Physical Analysis of Woif-Rayet Spectra
Authors: Vainu Bappu, M. K.
1958LIACo...8...40V Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Polarization of Comet Arend-Roland
Authors: Bappu, M. K. Vainu; Sinvhal, S. D.
1957Natur.180.1410B Altcode:
WHEN, last May, Comet Arend-Roland became a bright naked-eye object
in the northern hemisphere, we carried out a series of photoelectric
measures of the polarization of its coma at different phase angles. The
technique employed utilized a piece of `Polaroid' attached to
a rotatable six-position disk contained in the photometer. This
enables measurements of intensity to be made as the `Polaroid' is
turned through 60 dog. for each position of the disk. Standard B
and V filters employed in the UBV system, together with interference
filters having peak transmissions centred on 5890 A., 5000 A., 4700
A. and 4300 A. and half-widths of 80 A. were used for isolating the
different wave-lengths. Each of the three circular apertures behind the
`Polaroid' transmitted 3.7 square minutes of arc of the sky.
---------------------------------------------------------
Title: H and K Emission in Late-Type Stars: Dependence of Line Width
on Luminosity and Related Topics.
Authors: Wilson, O. C.; Vainu Bappu, M. K.
1957ApJ...125..661W Altcode:
The H and K emission lines of Ca II have been studied on 10-A/mm
spectrograms of 185 stars of types G, K, and M. Nearly all stars of
type G0 or later in the list of MK standards (Johnson and Morgan 1953)
have been included. Emission-line widths have been measured, as well
as displacements of the emission and absorption components. Tb e
displacements are determined with respect to nearby low-excitation
reversing- layer absorption lines. <P />When the logarithms of the
emission-line widths (corrected for instrumental width) are plotted
against the Yerkes absolute spectroscopic magnitudes, the points define
a straight line which extends over a 15-mag. range of M<SUB>v</SUB>
and which indicates that the line width varies as the one-sixth
power of the luminosity. Stars with weak or strong lines and of all
spectral types later than G0 seem to fit the linear relationship equally
well. The widths therefore cannot be dependent upon line intensity or
stellar surface temperature. <P />Evidence from the solar spectrum,
from ζ Aurigae, from Hyades stars, and from four visual binaries
point to the conclusion that the relationship described here is not
of a statistical nature. Therefore, it is probable that the Ca II
emission-line widths can be used as luminosity indicators. Internal
consistency considerations indicate that one good spectrogram should
fix the absolute magnitude of any late-type star with suitable lines
to within ±05 mag. <P />It is found that,for displacements within ±6
km/sec, negative values are more frequent than positive for the emission
components of H and K. On the other hand, between +4 and -4 km/sec,
positive values are more common for the absorption components. The
naive interpretation is that the emitting layer is rising and that
the absorbing material is falling slowly inward. Statistics of the
larger displacements common among the intrinsically luminous stars are
discussed briefly. In particular, it is found that among the M-type
giants and supergiants the negative displacements of the absorption
components are not correlated with absolute magnitude.
---------------------------------------------------------
Title: Spectrophotometry of WoIf-Rayet binary systems.
Authors: Bappu, M. K. Vainu; Sinvhal, S. D.
1955AJ.....60..152B Altcode:
Spectra obtained at the cassegrain focus of the Mt. Wilson 6o-inch
telescope over two seasons of observing have been used to study
the variation of emission line intensities and the profiles of a
few Wolf-Rayet binary systems. The binaries chosen are HD 214419,
HD 193576 and HD 193928 having periods of 1.64, 4.21 and 21.64 days,
respectively. Of these three, only two have been known to be eclipsing
variables. HD 214419. Hiltner (1950) has found by photoelectric methods
that the intensity of Heii 4686 in the binary reaches a maximum during
conjunctions and~a minimum at elongations. We have measured equivalent
widths at different phases for the lines Heii 6560, Hei 5875, Heii 5411
and Niv 4058. The equivalent widths of all these lines have a pattern
of behavior identical to that of Heii 4686, in that all of them show
increased intensities at primary and secondary minima with a lower value
of intensity at elongations. On certain nights the emission intensity
is considerably above average as noted by Hiltner. On such occasions,
there is corresponding increase in the intensity of the other lines
showing that a change in the general overall excitation mechanism
is the responsible agent for the fluctuation. There are no very
conspicuous changes with phase in the profiles of X4686 as has been
noted in the case of HD 193576. Nearly always at the primary minimum
when the Wolf-Rayet star is behind its companion, the X4686 profile
has a sharp peak at the centre with wide distended wings. At secondary
mini- μm when we receive radiation primarily from the Wolf-Rayet
star a well rounded profile results with a slight asymmetry on the
long wavelength side. The shapes at primary minimum of the profiles of
Heii 4686, Heii 6560, Heii 5411 and Niv 4058 resemble the curves that
would result, were the profiles outside eclipse modified by electron
scattering. There is evidence that the half-widths of Niv 4058 increase
at primary minimum. Such a result may be obtained if self-reversal
effects are conspicuous at primary minimum, or if the macroscopic
motions in the circulatory system of gas around the two components
are appreciable. The former alternative may be disregarded since the
profiles do not suggest any self-reversal effects. An interesting
feature is the development of intense violet edges immediately after
the primary and secondary minima. All the Heii lines develop such a
violet edge and this pattern is followed by the Hei lines at XX5875
and 4471. It is difficult to observe this effect in the violet wing
of ~656o since the io~a-F emulsion used has a dip in sensitivity in
this wave-length region. HD 193576. Well-widened spectra in the blue
region for this star have been used in the determination of equivalent
widths for Heii 4860, Heii 4686, Nv 4603 and Niv 4058. When plotted with
phase the lines Heii 4686 and Niv 4058 have negligible eclipse effects
at primary minimum. Heii 4860 and Nv 4603 have minimum intensities
at primary minimum, in the latter case probably caused by its own
intense violet edge coupled with the violet edge of ~46I9 of Nv. HD
193928. Large scale variations in the emission-line intensities of
the violet edges of Hei 4471 and Nv 4603 are easily noticeable. At
certain phases X4860 as well as Heii 4686 develop humps on the long
wave-length side of the profile. In the case of HD 214419 we find that
the increase in brightness at primary and secondary minima is shared
by all the emission lines measured. In HD 193576, Heii 4860 and Nv
4603 do not share the behavior of Heii 4686 and Nvi 4058. It would be
of great interest to obtain photoelectric light curves of this star
in the light of Heii 3206 and Niv 3483. One of us (Bappu 1951) has
suggested that the increase in intensity of the emission lines in HD
214419 could be explained on the basis of a common envelope model. Such
a situation would demand that the abnormal behavior be shared by all the
emission lines together, a phenomenon that we have found to exist in
HD 214419. The validity of the common-envelope hypothesis would cease
to exist in those systems that are not close binaries. Verification
of this hypothesis might therefore be made by carrying out programs of
emission line photometry in WolfRayet binary systems having different
periods. Bappu, M. K. V. 1951, Harvard thesis. Hiltner, W. A. 1950,
Ap. J. 112, 447. U. P. Government Astronomical Observatory, Banaras,
India.
---------------------------------------------------------
Title: Emission-Line Profiles from Expanding Envelopes.
Authors: Vainu Bappu, M. K.; Menzel, D. H.
1954ApJ...119..508V Altcode:
We have developed a method for calculating the emission4ine profiles
from an expanding envelope. The method applies to an envelope where the
emission intensity varies with latitude. Some typically illustrative
cases are considered.
---------------------------------------------------------
Title: Magnitudes and colours of some members of the Perseus Cluster
Authors: Vainu Bappu, M. K.
1954MNRAS.114..687V Altcode: 1954MNRAS.114..687B
No abstract at ADS
---------------------------------------------------------
Title: A photoelectric study of early-type supergiants around h and
χ Persei
Authors: Bappu, M. K. Vainu
1954MNRAS.114..680B Altcode:
Photoelectric colours and magnitudes for thirty early-type stars,
classified as supergiants belonging to the double cluster in
Perseus, have been determined with the aid of the Lick 1 -inch
refractor. Measures of four stars in Harvard Standard Region Ciz
were used for the tie-in to the (P, V) system. A general increase of
absorption is found as one passes from h to Persei, in accordance with
the earlier conclusions of Miss Pismis. A considerable non-uniformity
of interstellar absorption exists around the cluster. The supergiants
of type Bz and the Bo, Bo , Bi and Bz stars of luminosity class III
yield a distance modulus of 11m.7 for the cluster of supergiants,
corresponding to a distance of z z kps. Using the new value of
the distance modulus, absolute magnitudes have been calculated for
supergiants of other spectral classes. The number of stars used in
this investigation is too few to give an estimate of the dispersion
in Mv for these early-type supergiants.
---------------------------------------------------------
Title: The variation of emission-line intensities in CQ Cephei.
Authors: Bappu, M. K. Vainu
1952AJ.....57....6B Altcode:
The binary nature of the NJolf Rayet star HD 214419 was first
noted by McLaughlin and Hiltner,' at Michigan in 1941. Shortly
thereafter Gaposchkin2 showed the star to be an eclipsing system
with two well-defined minima. Hiltner3 recently studied the system
photoelectrically and obtained light-curves in the ultraviolet
and yellow regions of the spectrum as well as a light curve of the
emission line 4686A of Heii. The variation of 4686 differed from
that of the integrated case in that it had maxima at conjunctions and
minima at elongations, or in other words the geometry of the system
is such that 4686 is most intense when either star is eclipsed. To
determine whether other lines of Heii and * Of papers presented
at the Eighty-sixth Meeting of the American Astronomical Society,
East Cleveland, Ohio, December 26-29, 1951. those of nitrogen have
a variation with phase similar to that of 4686A, spectra were taken
throughout the 1.64 day period and central intensities, corrected for
the eclipse of the continuum, determined. The Heii lines X4861, X4542,
X4026, were eclipsed at both primary and secondary minima, with the
intensity of emission outside eclipse immediately after primary minimum,
lower than the intensity at third quadrature. The lines of nitrogen,
Niii 4528, Niv 4058, Nv 4603, have a variation with phase similar to
Heii 4861, but the intensity at first quadrature is greater than at
third quadrature. There is slight evidence that the depths of primary
minima are different for NIlI, Niv and. Nv, in that Nv has the smallest
depth and Niii the largest, but the material analyzed so far is very
little to establish this definitely. Hoěver, if this is real, it shows
that Nv is less eclipsed compared to the NIlI zone. From geometrical
considerations, it is possible that Nv is present in a higher layer
of the atmosphere than Niii, or in other words a positive excitation
gradient is present in the atmosphere. The presence of a secondary
minimum in the light curves of HIl 4861, Niv 4058 and other lines of
nitrogen indicates that a fair contribution to the overall emission
comes from a region in between the two stars. The differences between
the intensities at first and third quadratures may be explained as due
to the asymmetric distribution of the emission. If one assumes that
the system of GQ Cephei is a very close binary with a common envelope
in which 4686A is excited, the light curve can be explained as due to
the changes in the degree of occultation of this emission envelope. In
such a picture more of the envelope is occulted at first and third
quadratures than at times of primary and secondary minima. But as the
other Heii lines are not present so far out from the center of mass
of the system, it is possible that a fluoresence mech nism involving
Lyman a, as Bowen4 has suggested, is responsible for the excitation
of 4686A. If so the light-curve of Heii 3203 should be identical to
those of Heii 4861, and Niv 4058, and hence a study of its variation
in this eclipsing system would be valuable. I.Pub. A.S.P. 53, 328,
1941. 2. Ap. J. 100, 242, 1944. 3. Ap. J. 112, 477, 1950. 4. Ap. J. 8 ,
1, 1935. Iount Wilson and Palomar Observatories, Pasadena, Calff.
---------------------------------------------------------
Title: The Problem of Wolf-Rayet Atmospheres.
Authors: Bappu, Manali K. V.
1952PhDT.........1B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The Nature of Comets
Authors: Vainu Bappu, M. K.
1952ASPL....6..229V Altcode: 1952ASPL..279.....V
No abstract at ADS
---------------------------------------------------------
Title: A spectroscopic study of Wolf-Rayet stars.
Authors: Bappu, M. K. V.
1951AJ.....56..120B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: On the Light Curves of RX Librae and TV Canis Majoris
Authors: Bappu, M. K. Vainu
1951BHarO.920...10B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: A spectroscopic study of Wolf-Rayet stars.
Authors: Bappu, M. K. Vainu
1951AJ.....56R.120B Altcode:
A study has been made of the profiles and total intensities of the
emission lines of seven bright Wolf-Rayet stars in Cygnus, three
of which belong to the carbon sequence and the rest to the nitrogen
sequence. The well known eclipsing binary CQ Cephei was also included
on the program, and the variations in the profiles of the emission
lines and their total intensities during a cycle investigated. The
broad emission band X4058, tentatively identified as due to Niv,
has been found to be split into three components with wave lengths of
4044, 4057, and 4066 A. The lines X4044 and X4066 have been tentatively
identified as due to Nii and Ciii, respectively. The line X4066 Ciii is
moderately strong in carbon stars and as carbon lines have been found in
nitrogen stars this identification is probably correct. The flat-topped
nature of X4058, as shown by Beals to exist in BD 3504001, can then
be explained as due to the *Of papers presented at the Eighty-fifth
Meeting of the American Astronomical Society, Washington, D. C., J'ine
20-23, 1951. blending by physical causes of these components. The
line ~5696 in carbon stars, identified as due to Ciii, has been
observed to have a short wavelength component, X568 I, which has been
tentatively identified with the 3s1P0-3P1D transition of Nii. If such an
identification is correct, one would expect the transition 3S3PO~3p3P,
X4630, to be observable and of medium intensity. The observation
of this line is difficult because of the violet-absorption edge of
X4650 due to Ciii. Nevertheless, the line has `been detected in BD
3504013. The occurrence of central reversals in WolfRayet stars is a
rare phenomenon. The spectrograms of BD 3504001 reveal a deep core for
~4686 Heii, and a faint one for X54I I Heii. These might be central
reversals or they may possibly be due to a non-uniform distribution
of the emission on the stellar surface. Intrinsic variations of the
spectral lines, as has been shown by Struve' to exist in HD 151932,
have been found in two stars of the nitrogen sequence, BD 3703821 and BD
3504(>()I. The emission line X4603 Nv and its violet-edge experience
changes in intensity. The line X4640 of Niii, and the Niii lines blended
with N4542 Heii as well as ~447I Hei also show marked fluctuations. In
the case of the eclipsing variable CQ Cephei, the profile of ~4686
Heii has been determined at different phases. While changes in form
and intensity are immediately apparent, no marked asymmetry, as has
been found by Beals2 for lIOL in V444 Cygni, has been found here. The
intensities of the band X4640 have a curve of variation with phase,
similar to the N4686 light curve derived recently by Hiltner.1 The
line N4058 Niv has marked violet absorption edges at both primary and
secondary minima. The changes in intensity of X4542 and X447 I are
similar to those found by Mu~nch4 in V444 Cygni. I.Ap. J. 100, 198,
1944. 2.M. N. 104, 205, 1944. 3.Ap. J. 112, 477, 1950. 4.Ap. J. 112,
266, 1950. Harvard College Observatory, Cambridge, Mass.
---------------------------------------------------------
Title: The Spectrum of the Light of the Night Sky during the Recent
Sunspot Maximum.
Authors: Vainu Bappu, M. K.
1950ApJ...111..201V Altcode: 1950HarRe.336....1B
No abstract at ADS
