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Author name code: wilson-olin
ADS astronomy entries on 2022-09-14
author:"Wilson, Olin C." 

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Title: VizieR Online Data Catalog: Ca II H and K Measurements Made
    at MWO (Duncan+ 1991)
Authors: Duncan, D. K.; Vaughan, A. H.; Wilson, O. C.; Preston,
   G. W.; Frazer, J.; Lanning, H. H.; Misch, A.; Mueller, J.; Soyumer,
   D.; Woodard, L.; Baliunas, S. L.; Noyes, R. W.; Hartmann, L. W.;
   Porter, A.; Zwaan, K.; Middelkoop, F.; Rutter, R.; Mihalas, D.
2005yCat.3159....0D    Altcode:
  Summaries are presented of the photoelectric measurements of stellar
  CaII H and K line intensity made at Mount Wilson Observatory during
  the years 1966-1983. These results are derived from 65,263 individual
  observations of 1296 stars. For each star, for each observing season,
  the maximum, minimum, mean, and variation of the instrumental H and
  K index "S" are given, as well as a measurement of the accuracy of
  observation. A total of 3110 seasonal summaries are reported. <P />These
  observations were obtained with two instruments, HKP-1 and HKP-2. The
  HKP-2 instrument is a four-channel chopping spectrometer which records
  counts in 1.09{AA} FWHM triangular bandpasses centered in the H and
  K lines as well as in two 20{AA} reference bandpasses centered on
  3901.067 and 4001.067{AA}. The stellar activity is expressed by the
  index S defined as <P />S = {alpha} (Nh+Nk)/(Nr+Nv) <P />where Nh and
  Nk are the counts (corrected from background) in the H and K lines,
  Nr and Nv those in the reference continuum bandpasses, and {alpha}
  is a constant of proportionality used to correct for night-to-night
  instrumental variations. Higher values of S generally correspond to
  higher levels of chromospehric activities. <P />Factors which effect the
  ability to detect stellar activity variations and accurately measure
  their amplitudes such as the accuracy of the H and K measurements and
  scattered light contamination are discussed. Relations are given which
  facilitate intercomparison of "S" values with residual intensities
  from ordinary spectrophotometry, and for converting measurements to
  absolute fluxes. <P />(1 data file).

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Title: Chromospheric Variations in Main-Sequence Stars. II.
Authors: Baliunas, S. L.; Donahue, R. A.; Soon, W. H.; Horne, J. H.;
   Frazer, J.; Woodard-Eklund, L.; Bradford, M.; Rao, L. M.; Wilson,
   O. C.; Zhang, Q.; Bennett, W.; Briggs, J.; Carroll, S. M.; Duncan,
   D. K.; Figueroa, D.; Lanning, H. H.; Misch, T.; Mueller, J.; Noyes,
   R. W.; Poppe, D.; Porter, A. C.; Robinson, C. R.; Russell, J.; Shelton,
   J. C.; Soyumer, T.; Vaughan, A. H.; Whitney, J. H.
1995ApJ...438..269B    Altcode:
  The fluxes in passbands 0.1 nm wide and centered on the Ca II H
  and K emission cores have been monitored in 111 stars of spectral
  type F2-M2 on or near the main sequence in a continuation of an
  observing program started by O. C. Wilson. Most of the measurements
  began in 1966, with observations scheduled monthly until 1980, when
  observations were scheduled sevral times per week. The records, with
  a long-term precision of about 1.5%, display fluctuations that can be
  identified with variations on timescales similar to the 11 yr cycle of
  solar activity as well as axial rotation, and the growth and decay of
  emitting regions. We present the records of chromospheric emission and
  general conclusions about variations in surface magnetic activity on
  timescales greater than 1 yr but less than a few decades. The results
  for stars of spectral type G0-K5 V indicate a pattern of change in
  rotation and chromospheric activity on an evolutionary timescale, in
  which (1) young stars exhibit high average levels of activity, rapid
  rotation rates, no Maunder minimum phase and rarely display a smooth,
  cyclic variation; (2) stars of intermediate age (approximately 1-2
  Gyr for 1 solar mass) have moderate levels of activity and rotation
  rates, and occasional smooth cycles; and (3) stars as old as the Sun
  and older have slower rotation rates, lower activity levels and smooth
  cycles with occasional Maunder minimum-phases.

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Title: CA II H and K Measurements Made at Mount Wilson Observatory,
    1966--1983
Authors: Duncan, Douglas K.; Vaughan, Arthur H.; Wilson, Olin C.;
   Preston, George W.; Frazer, James; Lanning, Howard; Misch, Anthony;
   Mueller, Jean; Soyumer, David; Woodard, L.; Baliunas, Sallie L.;
   Noyes, Robert W.; Hartmann, Lee W.; Porter, Alain; Zwaan, Cornelis;
   Middelkoop, Frans; Rutten, Rene G. M.; Mihalas, Dimitri
1991ApJS...76..383D    Altcode:
  Summaries are presented of the photoelectric measurements of stellar
  Ca II H and K line intensity made at Mount Wilson Observatory during
  the years 1966-1983. These results are derived from 65,263 individual
  observations of 1296 stars. For each star, for each observing season,
  the maximum, minimum, mean, and variation of the instrumental H and
  K index 'S' are given, as well as a measurement of the accuracy of
  observation. A total of 3110 seasonal summaries are reported. Factors
  which affect the ability to detect stellar activity variations and
  accurately measure their amplitudes, such as the accuracy of the H and K
  measurements and scattered light contamination, are discussed. Relations
  are given which facilitate intercomparison of 'S' values with residual
  intensities derived from ordinary spectrophotometry, and for converting
  measurements to absolute fluxes.

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Title: Ca II H and K Flux Monitoring in Cool Stars: Rotation and
    Activity Cycles
Authors: Robinson, C. R.; Baliunas, S. L.; Bennett, W.; Briggs, J.;
   Frazer, J.; Noyes, R. W.; Shelton, C.; Woodard, L.; Vaughan, A. H.;
   Wilson, O. C.
1989BAAS...21.1115R    Altcode:
  No abstract at ADS

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Title: The Mount Wilson Observatory HK Project: The Continuing
    Analysis of Rotation and Stellar Magnetic Cycles
Authors: Baliunas, S. L.; Bennett, W.; Briggs, J.; Frazer, J.; Noyes,
   R. W.; Robinson, C. R.; Shelton, C.; Woodard, L.; Vaughan, A. H.;
   Wilson, O. C.
1988BAAS...20Q.994B    Altcode:
  No abstract at ADS

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Title: Stellar Activity Cycles and Rotation in Cool Stars Observed
    from Mt. Wilson Observatory
Authors: Baliunas, S. L.; Briggs, J.; Frazer, J.; Noyes, R. W.;
   Robinson, C. R.; Carroll, S.; Donahue, R. A.; Shelton, C.; Woodard,
   L.; Vaughan, A. H.; Wilson, O. C.
1988BAAS...20Q.697B    Altcode: 1988BAAS...20Z.697B
  No abstract at ADS

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Title: Recognition and classification of strong-CN giants.
Authors: Keenan, Philip C.; Yorka, Sandra B.; Wilson, Olin C.
1987PASP...99..629K    Altcode:
  Fifty of the stars designated as super-metal-rich by Spinrad and
  Taylor (1969) are classified here on the Revised MK System. Positive
  CN indices are assigned in recognition of the characteristic excesses
  of carbon and nitrogen in their atmospheres, as compared to normal
  Population I stars. For only a few of the stars, an abnormal strength
  of the iron lines or of Ca 4226 A is so noticeable that they need to
  be distinguished by positive indices for these metals.

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Title: Activity Cycles of Lower Main-Sequence Stars: Eighteen Years
    of Research
Authors: Baliunas, S. L.; Donahue, R. A.; Horne, J. H.; Noyes, R. W.;
   Porter, A.; Gilliland, R.; Duncan, D. K.; Frazer, J.; Lanning, H.;
   Misch, A.; Mueller, J.; Soyumer, D.; Vaughan, A. H.; Wilson, O. C.;
   Woodard, L. A.
1984BAAS...16R.899B    Altcode:
  No abstract at ADS

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Title: Photoelectric measures of chromospheric H and K and He in
    giant stars.
Authors: Wilson, O. C.
1982ApJ...257..179W    Altcode:
  The coude scanner of the 100-inch telescope was used to measure
  the fluxes at the centers of H and K of Ca II and at the position of
  H-epsilon, and its antiposition, in about 200 late-type giant stars. For
  the large majority of class III giants, it was found that the total
  chromospheric radiation of H and K and of H-epsilon is constant in
  amount for G8 to early M-type stars with respect to the energy in
  the V band, and that the two Ca II lines together emit about three
  times as much energy as does H-epsilon. In the Hyades main sequence
  the efficiency of the transfer of energy from the total outflow
  into the chromosphere increases from the bluer to the redder stars,
  whereas the converse is true in the normal giants. Evidence is given
  that main-sequence stars with H and K emission also have emission
  in H-epsilon that is considerably weaker, with respect to H and K,
  than in the giants.

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Title: Activity Cycles in Other Stars
Authors: Wilson, O.; Vaughan, A.; Kraft, R.; Preston, G.
1981S&T....62..312W    Altcode:
  No abstract at ADS

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Title: The activity cycles of stars.
Authors: Wilson, O. C.; Vaughan, A. H.; Mihalas, D.
1981SciAm.244b..82W    Altcode: 1981SciAm.244...82W
  No abstract at ADS

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Title: The activity cycles of stars
Authors: Wilson, O. C.; Vaughan, A. H.; Mihalas, D.
1981SciAm.244b.104W    Altcode: 1981SciAm.244..104W
  The activity cycle of the sun is reviewed with attention to the
  contributions of Galileo, Schwabe, Wolf, Maunder, Carrington, Hale,
  Babcock and Parker. The use of the H-K photometer in the observation of
  the chromospheric variability of 91 sun-like stars at the Mount Wilson
  Observatory is discussed. It is estimated that more than half of the
  main-sequence stars less massive than 1.5 solar masses may show cyclic
  behavior. The chromospheric variations for 12 sunlike stars are given.

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Title: Stellar Spectroscopy - Stellar Chromospheres - Magnetic
    Ap-Star - Dwarf Novae - Variable Stars
Authors: Wilson, O.; Vaughan, A.; Preston, G.; Wolff, S. C.; Borne, K.;
   Wade, R.; Greenstein, J.; Schneider, D. P.; Mochnacki, S.; Oke, J. B.
1979haob.rept..724W    Altcode:
  No abstract at ADS

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Title: Chromospheric variations in main-sequence stars.
Authors: Wilson, O. C.
1978ApJ...226..379W    Altcode:
  An analysis is given of fluxes measured in 1-A bands centered on the Ca
  II H and K lines for a sample of 91 main-sequence stars, extending from
  about F5 to M2, over time intervals of nine to 11 years. The results are
  discussed separately for a set of 18 stars with minimal chromospheric
  fluxes used as standards, the program stars of spectral types F7 to G3,
  the program stars of types G5 and later, as well as the sun. K/H ratios
  are determined and compared for the different groups of stars. It is
  tentatively concluded that: (1) no stellar chromospheres are likely
  to be constant in time; (2) short-term fluctuations tend to increase
  in size with average flux; (3) cyclical variations occur with periods
  ranging from about 7 years to probably at least twice as long; (4) the
  stellar cycles observed in H and K flux should be regarded as evidence
  for analogs of the solar cycle; and (5) the incidence of complete or
  probable partial cycles increases toward later spectral types.

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Title: Flux measurements of Ca II and K emission.
Authors: Vaughan, A. H.; Preston, G. W.; Wilson, O. C.
1978PASP...90..267V    Altcode:
  A four-channel photon-counting spectrophotometer (designated HKP-2)
  is described which is designed for measuring stellar chromospheric
  calcium emission. The HKP-2 is calibrated, and its performance and
  accuracy evaluated, by observing 63 of Wilson's (1968) program stars
  on the same nights with both the HKP-2 and a coude scanner designated
  HKP-1. The results of the observations are discussed in terms of
  the calibration of mean H-K flux indices, variations in individual
  stellar fluxes, the flux ratio for H and K, and the instrument color
  index. It is shown that the HKP-2 provides satisfactory performance in
  the measurement of stellar chromospheric emission in a manner closely
  analogous to the method of Wilson and that a single observation yields
  a color index as well as flux indices for H and K that can be calibrated
  and transferred unambiguously to Wilson's system of measurement.

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Title: Stellar chromospheres for fun and profit.
Authors: Wilson, O. C.
1977BAAS....9..585W    Altcode:
  No abstract at ADS

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Title: Effects of heavy element abundance on spectroscopic
    luminosities of G5 - K0 giants.
Authors: Keenan, P. C.; Wilson, O. C.
1977ApJ...214..399K    Altcode:
  Spectral classification has been carried out on coude' spectrograms
  (9 A mm -1) for 13 semibarium stars (stars with slight excesses of
  heavy metals) and for two barium stars. The luminosity classes assigned
  from ratios of lines of iron-peak elements should be independent of
  chemical composition. These luminosity classes place the observed
  semibarium stars on, or very slightly above, the main giant sequence,
  in agreement with the K-line absolute magnitudes. The two barium stars
  (o Vir and HD 205011) are also typical giants in luminosity. Subject
  headings: stars: abundances - stars: late-type - stars: luminosities

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Title: Absolute magnitudes of stars from widths of chromospheric Ca
    II emission lines.
Authors: Wilson, O. C.
1976ApJ...205..823W    Altcode:
  Absolute magnitudes of about 700 late-type subgiants, giants, and
  supergiants are derived from measures of the widths of the chromospheric
  emission components of the Ca ii K line. They are tabulated along
  with other pertinent information. The data are essentially complete
  for all suitable stars down to m = 5.0 and declination 250. The moduli
  derived from the Mv(K) are plotted against the trigonometric parallaxes
  for all stars for which the latter have weights &gt;20. It is found
  that there is a systematic difference in the fit to the m - M = -s -
  5 log curve for stars with b &lt; 250 compared to those with b &gt;
  250. Since the numbers of stars in these two groups are equal, the
  difference is believed to originate with the parallaxes. Estimates
  against nearby Fe i lines have been made for the strength of Sr ii
  A4077, which is a luminosity criterion for these stars. When the
  logarithms of the A4077 intensities are plotted against the Mv(K),
  the bulk of the stars in the diagram fall approximately along a linear
  relationship. However, there is a group of stars between Mv(K) =
  +1.5 and -3 for which the estimated A4077 intensities are too strong,
  compared to the average for the other stars, by amounts well in excess
  of the errors of estimation. Further investigation indicates that the
  G-K stars in this group are probably barium stars, but M-type stars
  also participate in the Sr ii anomaly. The color-magnitude diagram
  constructed from the Mv(K) has several interesting features which are
  discussed in the text. In particular, the C-M diagram of NGC 188 by
  Sandage forms an excellent lower boundary to the assemblage of field
  stars. Subject headings: Ca ii emission - stars: late-type - stars:
  luminosities

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Title: Chromospheric Variations in Main Sequence Stars
Authors: Wilson, O. C.
1976IAUS...71..447W    Altcode:
  No abstract at ADS

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Title: Ira S. Bowen (1898-1973)
Authors: Wilson, O. C.
1973S&T....45..212W    Altcode:
  No abstract at ADS

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Title: Summary
Authors: Wilson, O. C.
1973NASSP.317..305W    Altcode: 1973stch.coll..305W; 1973IAUCo..19..305W
  No abstract at ADS

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Title: I. S. Bowen 1898 - 1973 Februar 6th.
Authors: Wilson, O. C.
1973S&T....45R.212W    Altcode:
  No abstract at ADS

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Title: Ira Sprague Bowen (1898 - 1973).
Authors: Wilson, O. C.
1973S&T....45Q.212W    Altcode:
  No abstract at ADS

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Title: A Preliminary Investigation of the Dependence of Mv (K) on
    [Fe/H]
Authors: Wilson, O. C.; Olsen, E. H.; Kjaergaard, P.
1972QJRAS..13..161W    Altcode:
  No abstract at ADS

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Title: Widths of CA II Chromospheric Emission Lines as a Measure of
    Stellar Luminosity
Authors: Wilson, Olin C.
1970PASP...82..865W    Altcode:
  No abstract at ADS

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Title: Dependence of Chromospheric Emission upon Bolometric Luminosity
    for the Hyades
Authors: Wilson, O. C.
1970ApJ...160..225W    Altcode:
  Fluxes in the centers of the H and K lines were measured for sixty-five
  Hyades stars between F4 and KS. Analysis of these measures shows that,
  in terms of bolometric luminosity, theradiation in the chromospheric
  H and K emission lines increases by a factor of 2 between B - V =
  0.45 and B - V = 1.25. Other results give the emission as a function
  of the local continuum, as well as the true emission ratios for stars
  in this color range.

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Title: Calcium emission intensities as indicators of stellar age.
Authors: Wilson, O.; Woolley, R.
1970MNRAS.148..463W    Altcode:
  Fresh data are presented concerning the calcium emission intensities
  of 325 main-sequence late-type stars estimated by one of the authors
  (0. W.). These are compared with parameters of the galactic orbits
  of the stars according to methods worked out at R.G.O. A very clear
  correlation is found between the calcium emission intensities and
  the eccentricities and box angles (inclinations) of the orbits. This
  reinforces the view that main-sequence stars with strong calcium
  reversals are young stars, and have near circular orbits with low
  inclinations to the galactic plane; while stars with feeble emissions
  are old stars which have, statistically, high eccentricities and high
  inclinations to the galactic plane.

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Title: High-Dispersion Classification of K2-M6 Giants of High and
    Low Velocity
Authors: Deutsch, A. J.; Wilson, O. C.; Keenan, P. C.
1969ApJ...156..107D    Altcode:
  The classification of early M-type giants by the usual criteria of TiO
  band strengths has been tested by estimating ratios of weak atomic
  lines on coudé spectrograms of scale 9-10 A mm1. No systematic
  dif- ferences are found between the types given by the two methods
  for Population I stars and for high- velocity stars of intermediate
  Population II. Published V - I and U - I colors also give sequences in
  agreement with the spectral types. Although there is thus no evidence
  that TiO bands differ in strength between giants of the two popula-
  tions studied, in several of the M stars of high velocity a slight
  weakening of the stronger atomic lines ap- pears to be present. In
  several stars representing both populations, the absorption lines at
  Hy and Ho show intensity changes on a time scale of weeks or months;
  but other absorption lines and bands appear not to vary

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Title: Calibration Apparatus at Mt. Wilson and Mt. Palomar
Authors: Wilson, Olin C.
1969BAAS....1..154W    Altcode:
  No abstract at ADS

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Title: Chromospheric variations in main-sequence stars
Authors: Wilson, O. C.
1969lls..symp..103W    Altcode:
  No abstract at ADS

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Title: Flux Measurements at the Centers of Stellar H- and K-Lines
Authors: Wilson, O. C.
1968ApJ...153..221W    Altcode:
  The coudé scanner of the 100-inch telescope has been used as a
  two-channel photometer to measure the fluxes at the centers of stellar
  H- and K-lines, for the purpose of initiating a search for stellar
  ana- logue~ of the solar cycle. From the Stromgren-Perry catalogue
  139 stars previously observed at 10 A mm1 dispersion were selected for
  this purpose and included most of those in which H-K emission had been
  seen on the spectrograms. Reasonable agreement between eye-estimated
  intensities and the photometric results shows that the procedure adopted
  is suitable for specifying chromospheric activity, but with an accuracy
  much improved over eye estimates. The probable error of a single
  measurement of a line is a little less than 2 per cent. No undoubted
  variations have been observed during a year's observation. However,
  the measures are discussed in connection with the Stromgren-Perry
  photometric parameters b - y, in1, C1. In this way it is possible to
  trace in some detail the course of chromospheric evolution as stars
  begin to move off the zero-age main sequence (ZAMS) toward the giant
  region. Doublet ratios of the chromospheric compo- nents of H and K are
  one of the by-products of the observations. They show that, in general,
  the optical thickness of the gas masses involved cannot be very great

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Title: Radial velocities of dK and dM stars.
Authors: Wilson, O. C.
1967AJ.....72..905W    Altcode:
  No abstract at ADS

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Title: Distance of the Hyades and Relation between Luminosity and
    CA II Emission-Line Widths
Authors: Wilson, O. C.
1967PASP...79...46W    Altcode:
  No abstract at ADS

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Title: Dwarf k- and m- Stars from the Catalogue of Vyssotsky et AL.
Authors: Wilson, O. C.
1967IAUS...30..145W    Altcode:
  No abstract at ADS

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Title: The masses of nine visual binary systems
Authors: Wilson, O. C.
1967mamt.book..241W    Altcode:
  No abstract at ADS

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Title: Age-Helium Content Correlations for Two Low-Mass Field
    Binary Systems
Authors: Faulkner, John; Iben, Icko, Jr.; Wilson, Olin C.
1966ApJ...146..271F    Altcode:
  It is shown that knowledge of a well-determined mass for a star
  ascending the subgiant branch would provide an important test
  of theories of stellar evolution. Recently determined masses for
  the systems ADS 755 and ADS 11479 suggest that the component stars
  formed from material that was richer in helium than would be thought
  appropriate to the relevant period of formation. In particular, the
  assumption that these stars are as old as the Galaxy itself implies
  initial helium contents &gt;= 30 per cent, in agreement with a recently
  proposed theory of the evolution of Population II stars.

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Title: Stellar Convection Zones, Chromospheres, and Rotation
Authors: Wilson, O. C.
1966ApJ...144..695W    Altcode:
  This paper is an attempt to connect the rotations of main-sequence
  stars with their chrom osheric properties and, hence, with the extent
  of their hydrogen convection zones. It is based on 10/mm spectrograms
  of 308 stars, with b - y &gt; 0 240 from the -Perry catalogue. On
  the zero-age main sequence it is found that rotational velocities of
  the order of V sin i &gt; 50 km/sec set in very abruptly at b - y =
  0.285, and Kraft's observations show that this is true also in the
  Hyades. However, similar rotational velocities are found among the field
  stars at the upper edge of the main- sequence band among spectral types
  G0-G5, and it is logical to suppose that these objects have evolved
  from the zero-age line near b - y = 0.285. A curve can be drawn in the
  (b - y) - Ci plane which separates the large from the small rotations,
  and this curve, therefore, approximates the evolutionary track of
  stars originating at b - y = 0.285 on the zero-age line. This curve,
  which divides the larger from the smaller angular momenta, applies
  to the members of spectroscopic binary systems as well as to single
  stars. Stars showing emission at H and K have a strong concentration to
  the zero-age line and extend up the main sequence to b - y = 0.30. It
  cannot be stated definitely that stellar chromospheres terminate
  near this point, but the evidence indicates that it is quite possible
  that they do. If so, the close agreement between the onset of larger
  rotations and the termination of chromospheres is very suggestive
  of the braking mechanism described by Schatzman. The implication,
  then, is that deep hydrogen convection ends at b - y = 0 285 on the
  zero-age line (spectral type F4), and the observations show that the
  change from deep to shallow convection must occur within a mass range
  of the order of 5 per cent.

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Title: Stellar Chromospheres
Authors: Wilson, O. C.
1966Sci...151.1487W    Altcode:
  No abstract at ADS

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Title: Chromospheric Activity as a Function of Age in Main-Sequence
    Stars
Authors: Wilson, O. C.; Skumanich, A.
1966IAUS...24...40W    Altcode:
  No abstract at ADS

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Title: A Preliminary Investigation of Lithium in Main Sequence
    Visual Binaries
Authors: Wilson, O. C.; Baum, W. A.; Ford, W. K., Jr.; Purgathofer, A.
1965PASP...77..359W    Altcode:
  No abstract at ADS

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Title: Stellar Chromospheres and Ca II H and K Emission
Authors: Wilson, O. C.
1965SAOSR.174..381W    Altcode:
  No abstract at ADS

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Title: The Strength of the li i Line in the Spectra of Main-Sequence
    f- and G-Type Stars.
Authors: Kraft, Robert P.; Wilson, Olin C.
1965ApJ...141..828K    Altcode:
  No abstract at ADS

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Title: Dependence of Chromospheric Activity upon Age in Main-Sequence
Stars: Additional Evidence.
Authors: Wilson, O. C.; Skumanich, Andrew
1964ApJ...140.1401W    Altcode:
  Spectrograms of 10 A/mm dispersion have been obtained of 142 field
  stars from the catalogue of Str6mgren and Perry for those objects with
  b - y &gt; 0.325. Mter elimination of known spectroscopic binaries
  and stars of higher luminosity, a sample of 114 main-sequence stars
  remains. In this sample seventeen stars showing H and K bright reversals
  are found, and all but two of these lie close to the lower boundary
  (zero-age edge) of the distribution in a Ci - (b - y) diagram. This
  result is taken as evidence in support of the view that chromospheric
  activity of main-sequence stars decreases with age. In particular,
  it removes the possibility that stars formed in large clusters differ
  significantly in respect to their chromospheric properties from those
  formed in small groups or singly.

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Title: Chromospheric Activity and Lithium
Authors: Wilson, O. C.
1964PASP...76..238W    Altcode:
  No abstract at ADS

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Title: Retirement of Dr. Ira S. Bowen
Authors: Wilson, O. C.
1964PASP...76..193W    Altcode:
  No abstract at ADS

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Title: The Distribution of Intensities of Bright H and K in dK Stars
    and the Rate of Star Production in the Galaxy
Authors: Wilson, O. C.
1964PASP...76...28W    Altcode:
  No abstract at ADS

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Title: Strength of the Li I Line in the Spectra of Main-Sequence F-
    and G-Type Stars.
Authors: Kraft, Robert P.; Wilson, Olin C.
1964AJ.....69Q.549K    Altcode:
  The strength of the Li I feature at X6708 has been estimated against
  X6703 of Fe I and X6718 of Ca I in the spectra of about 30 main-
  sequence F- and G-type stars. The stars were selected from Stro~mgren
  and Perry's photometric catalog on the b-y, c,, m1, system in the
  interval 0.33&lt;b-y&lt;0.42, without regard to c, or m1, or Ca II
  emission strength. From the limited material at hand, we conclude the
  following: (1) All stars showing strong Ca II emission show strong Li
  I in absorption, but Li I absorption occurs in strength in many stars
  without Ca II emission. (2) If, following Stro~mgren, we interpret
  the index c, as a nuclear age parameter, then there is no correlation
  between Li I strength and nuclear age. (3) There is no correlation
  between the Li I strength and the metal index mi.

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Title: The Spectrum of NGC 7027.
Authors: Aller, L. H.; Bowen, I. S.; Wilson, O. C.
1963ApJ...138.1013A    Altcode:
  Additional spectrograms of NGC 7027 have been obtained which
  extend the observations to substantially fainter lines than earlier
  studies. Photoelectric measurements were made of the stronger lines
  in the region between X 3100 and X 4700 and were used to calibrate
  the photographically determined intensities of all lines.

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Title: A Probable Correlation Between Chromospheric Activity and
    Age in Main-Sequence Stars.
Authors: Wilson, O. C.
1963ApJ...138..832W    Altcode:
  Observation shows that the average intensity of H and K emission
  is much higher for main-sequence stars of types G0-K2 in the Hyades,
  Praesepe, Coma, and Pleiades clusters than for similar local field stars
  and that it is appreciably higher for the Pleiades than for the other
  clusters. It is also found, from observations of local visual binaries,
  that the H-K intensities in the members of such pairs tend to be very
  similar when allowance is made for spectral-type differences. It is
  concluded that the most probable explanation of these facts is that
  the H-K intensity in a main-sequence star and hence the general degree
  of its chromospheric activity bear an inverse relationship to its
  age. This concept of chromospheric evolution is consistent with all
  the observations presented here, as well as with the known kinematical
  differences between dMe and ordinary dM stars. If, however, stars can be
  formed in the general field, as well as in clusters, then the observed
  differences in chromospheric activity would be related to place of
  origin rather than to age. The probable bearing of average surface
  magnetic-field strength on the question of chromospheric activity is
  discussed briefly.

---------------------------------------------------------
Title: Nebular absorption of He 3889 A.
Authors: Munch, G.; Wilson, O. C.
1963AJ.....68..287M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Lithium in a Main Sequence Star
Authors: Wilson, O. C.
1963PASP...75...62W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Nebular Absorption of He I λ3889.
Authors: Münch, G.; Wilson, O. C.
1963AJ.....68Q.287M    Altcode:
  The presence of an absorption line arising from the 2~5 metastable
  level of neutral helium in the spectra of the stars imbedded in the
  Orion Nebula was noticed long ago by 0. C. Wilson. Lately it has been
  shown by G. Mu~nch and 0. C. Wilson (Z. Astrophys. 56, 127, 1962)
  how the strength of this nebular absorption line may be related to
  the surface brightness of a homogeneous emission nebula. The lack
  of agreement between the surface brightness thus computed for the
  Orion Nebula with the observed value, has been interpreted in terms
  of density inhomogeneities in the nebula, independently postulated
  by Osterbrock on other grounds. Because this interpretation has been
  criticized by K. Wurm (Z. Astrophys. 52,149, 1961), new observational
  evidence related to the line in question is being obtained. In this
  communicatioi~, besides new data for the Orion stars, the results
  of the search for the absorption line in other emission nebulae are
  presented. So far the line has been detected in a number of stars in
  the complex M8- M20, in BD +6601675, exciting NGC 6822, in BD +6002522
  exciting NGC 7635, and in HD 64315, exciting star of NGC 2467. The stars
  imbedded in 20 other H II regions do not have detectable He I nebular
  absorption. Although a complete discussion of the data requires surface
  brightness determinations (corrected for interstellar and internebular
  extinction) not available yet, it is shown how the recent observations
  fully support the interpretation advanced earlier by Wilson and Mu~nch.

---------------------------------------------------------
Title: Internal Motions in the Planetary Nebula IC 4997
Authors: Wilson, Olin C.; O'dell, C. R.
1962PASP...74..511W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Relationship Between Colors and Spectra of Late Main-Sequence
    Stars.
Authors: Wilson, O. C.
1962ApJ...136..793W    Altcode:
  Spectrograms of 109 main-sequence stars of types G5 and later have
  been obtained at a dispersion of 10 A/mm and have been used to derive
  spectral types on the Yerkes system, based on ratios of metallic
  lines. A plot of the revised types against the old Mount Wilson
  types shows a very considerable scatter, which is believed to be
  due chiefly to errors in the Mount Wilson values. Nevertheless, even
  with the revised types, it is found that there is not a one-to-one
  correspondence between spectral type and photoelectric color for these
  field stars. Spectral types of 69 Hyades main-sequence stars have been
  estimated from 38 A/mm spectrograms. For these objects the correlation
  of type and color is appreciably closer than for the field stars. It
  is suggested, following an argument based on the Vogt-Russell theorem,
  that these facts imply a greater degree of chemical non-uniformity
  in the local main sequence than in that of the Hyades. A number of
  instances of anomalous intensities of the hydrogen lines and of CN
  bands among the local main-sequence stars are indicated.

---------------------------------------------------------
Title: On the Structure of the Orion Nebula. A Reply to K. WURM. With
    2 Figures in the Text
Authors: Münch, G.; Wilson, O. C.
1962ZA.....56..127M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: An Interpretation of the Late Main Sequence.
Authors: Wilson, O. C.
1961ApJ...133..457W    Altcode:
  Eggen's photoelectrically measured c6lors are plotted against spectral
  type for the main sequence below AS. It is found that the distribution
  of points in this diagram is fairly narrow from AS to G5, at which point
  it begins to widen. This width, which extends at least as far as Mi,
  is much too large to be attributable to errors in either the colors
  or the spectral types. It is noted also that the widening occurs in
  that region of the spectral sequence where the supply of electrons
  fiom hydrogen is diminishing to the point where the metals are coming
  into equilbrium with their own electrons. This leads to an attempt
  to account for the major features of the (P- V) -type diagram on the
  basis of a series of stellar atmospheres in which the metal-hydrogen
  radio is not constant and within which,for a given spectral type, there
  is an appreciable spread of temperature. The results are encouraging
  to a considerable degree, and, where discrepancies occur in the range
  G8-K2, they are in the sense to be reduced if differential blanketing
  effects are still appreciable It turns out that among main-sequence
  K-type stars a total range in the metal-hydrogen ratio of the order
  1:100 is necessary to account for the observed spread in the plot
  referred to above. Observations at 10 A/mm of stars of the same types
  near the upper and lower boundaries of the diagram show that they are
  spectroscopically distinguishable. All stars near the upper boundary
  (red stars) have much stronger H and K emission than do stars of the
  same types near the lower boundary (blue stars). Conversely, except at
  G8, the blue stars of given types all have stronger Balmer absorption
  lines than the corresponding red stars. These latter facts are accounted
  for, semiquantitatively, by the same assumptions as those which explain
  the spread in the (P - V) spectral-type diagram.

---------------------------------------------------------
Title: Spectrographic Observations of a Flare Star
Authors: Wilson, O. C.
1961PASP...73...15W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: A New Scale of Stellar Distances
Authors: Wilson, O. C.
1961SciAm.204a.107W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Observational Limitations to Mass Loss by Normal Late-Type
    Giants.
Authors: Wilson, O. C.
1960ApJ...132..136W    Altcode:
  Spectroscopic observations of H and K lines of Ca ii in several hundred
  late-type stars are discussed, and it is shown that the measured
  displacements provide no evidence for ejection of matter from normal
  giants earlier than MO. Also, some simple calculations show that the
  absence of true circumstellar lines from the spectra of these objects
  implies a rate of mass loss less than 10-10 0 per year. Hence if these
  stars must lose a substantial portion of their masses before becoming
  wbite dwarfs there appear to be only two alternatives: either they
  all must eventually evolve to M-type stars and remain such long enough
  to eject the necessary amount of matter; or they are ejecting matter
  at present but by some unknown mechanism which permits the process to
  escape observation. There is also a brief discussion of mass loss in
  genera] and with reference to a Herculis in particular.

---------------------------------------------------------
Title: A Suggested Mechanism for the Ejection of Matter from M-Type
    Stars.
Authors: Wilson, O. C.
1960ApJ...131...75W    Altcode:
  It is suggested that matter is ejected from M-type stars by the outward
  force due to a strong chromospheric Ly-a radiation A brief examination
  of the mechanism indicates that it may be capable of meeting the
  requirements set by the observations of expanding envelopes around
  these stars

---------------------------------------------------------
Title: Eclipses by Extended Atmospheres
Authors: Wilson, O. C.
1960stat.book..436W    Altcode: 1960S&SS....6..436W; 1960stat.conf..436W
  No abstract at ADS

---------------------------------------------------------
Title: A Color-Magnitude Diagram for Late-Type Stars Near the Sun.
Authors: Wilson, O. C.
1959ApJ...130..496W    Altcode:
  A color-magnitude diagram for late-type stars in the solar neighborhood
  is derived from measures of the widths of the bright H and K reversals
  in the spectra of stars for which photoelectric values of B - V are
  available. The diagram is filled out by the inclusion of stars with
  trigonometric parallaxes &gt;0'oso. From the plotted points it is
  possible to delineate with fair accuracy the limiting evolutionary
  track for the oldest galactic stars and to estimate the location of
  the break-off point from the main sequence. The corresponding age
  of the galaxy is about lOiS years, but this estimate is subject to
  improvement with the addition of further observations.

---------------------------------------------------------
Title: Accuracy of Absolute Magnitudes Derived from Widths of H and
    K Emission Components.
Authors: Wilson, O. C.
1959ApJ...130..499W    Altcode:
  Measures of the dths of the bright reversals in H and K in the sun and
  in the yellow giants of the Hyades are used to establish a calibration
  of absolute visual magnitude as a function of emission-line width. For
  giant and subgiant stars the probable error of a single measurement is
  j 0.26 mag., and the probable error due to intrinsic scatter is about
  I 0.20 mag. The latter quantity is determined from comparison with 24
  stars for which dir/ir &lt; 6 . A comparison with 29 main-sequence stars
  gives larger values of both measuring error and intrinsic scatter. It is
  suggested that the principal source of intrinsic scatter for all stars
  may be rotational widening. Further comparison with H and K measures
  in three supergiants in h and x Persei and in the K-type component of
  Aurigae indicates that the calibration is valid for stars as bright
  as Mv -6.

---------------------------------------------------------
Title: Location of Late Type High-Velocity Stars in the
    Color-Magnitude Diagram
Authors: Wilson, O. C.
1959PASP...71..338W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Internal Kinematics of the Orion Nebula.
Authors: Wilson, O. C.; Minich, Guido; Flather, Edith; Coffeen, Mary F.
1959ApJS....4..199W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: A preliminary color-magnitude diagram for late-type stars in
    the solar neighborhood
Authors: Wilson, O. C.
1959IAUS...10...39W    Altcode: 1959SAnAp...8...39W
  No abstract at ADS

---------------------------------------------------------
Title: Some Theoretical Apsects of H and K Emission in Late-Type
    Stars.
Authors: Hoyle, F.; Wilson, O. C.
1958ApJ...128..604H    Altcode:
  A velocity is defined in the subphotospheric convection zones of
  late-type stars that varies from star to star in the same way as the
  width of the emission lines H and K of Ca ii The quantity is tentatively
  identified as the velocity of hydromagnetic waves.

---------------------------------------------------------
Title: Internal Kinematics of the Planetary Nebulae
Authors: Wilson, O. C.
1958RvMP...30.1025W    Altcode: 1958IAUS....8.1025W
  No abstract at ADS

---------------------------------------------------------
Title: Limitations on Physical Theories of H and K Emission Lines.
Authors: Wilson, O. C.
1957ApJ...126..525W    Altcode:
  A satisfactory physical theory of the H and K emission lines in the
  sun and stars has not yet been developed. By consideration of existing
  observations, certain requirements of and limitations upon such theories
  are established. If rO is the optical thickness in the line center, N
  the number of Ca ii ions per square centimeter vertical column, L the
  luminosity (visual), and AXD the Doppler width, the following items
  must be accounted for: A. Emission produced in optically thin layers
  (ro 1). (1) AXD L1/6. (2) N unrestricted except for upper limit on
  ro. (3) Mechanism for adequate emission from thin layers. B. Emission
  produced in optically thick layers (10 &lt; ro &lt;- l0 ). (1) Both
  AXD and N must vary appropriately with L. (2) The rate of variation
  of AXD with L must lie within the maximum and minimum rates, which,
  together with the corresponding variations of N, are, respectively,
  AXD L1/5, N L-1/4, and AXD L1/9, N L1/2.

---------------------------------------------------------
Title: H Emission in Late-Type Star.
Authors: Wilson, O. C.
1957ApJ...126...46W    Altcode:
  Intensities of HE emission are estimated in 185 late-type stars
  and compared with those of the K line of Ca ii. Although there is
  a statistical tendency toward a correlation between the HE and K
  intensities, there is also a large scatter, indicating that the ratio
  of HE to K is widely variable.

---------------------------------------------------------
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: The Analysis of the Chromosphere of Zeta Aurigae
Authors: Wilson, O. C.
1957JRASC..51...70W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Simultaneous Spectrographic and Photometric Observations of
    the Short-Period Variables SX Phoenicis and CC Andromedae.
Authors: Wilson, O. C.; Walker, Merle F.
1956ApJ...124..325W    Altcode:
  Radial velocity-curves and light-curves in three colors are derived
  from simultaneous spectrographic and photoelectric observations made
  at Palomar in 1953 and 1954. For both SX Phoenicis and CC Andromedae
  maximum brightness lags behind maximum size, as deduced from the
  radial velocities, by a quarter-period, as is true of the cepheid
  variables. The light-amplitude of SX Phoenicis is widely variable, but
  corresponding variations in the velocity-amplitude cannot be established
  with certainty. On the other hand, there is an obvious relationship
  between the light- and velocity-amplitudes of CC Andromedae, which
  seems to be the same as that for Scuti. It is probable that these two
  stars, together with DQ Cephei, belong to the same class of variable
  and that they may be considerably brighter than main-sequence stars
  of the same spectral type.

---------------------------------------------------------
Title: The New Cassegrain Spectrograph for the Mount Wilson 60-Inch
    Telescope
Authors: Wilson, O. C.
1956PASP...68..346W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Proportionality of Nebular Red Shifts to Wave Length.
Authors: Minkowski, R.; Wilson, O. C.
1956ApJ...123..373M    Altcode:
  Measures of the red shift /Xo for the colliding galaxies Cygnus A give
  the value 16812 + 9 km/sec for the mean wave length 3830 A and 16798 +
  7 km/sec for the mean wave length 6472 A. The relative change in the red
  shift with wave length is less than 3 X 10- per 1000 A. Combination of
  the optical results with those by Lilley and McClain for the 21-cm
  hydrogen line shows that the relative change is lessthan3 X 10-
  per 1000A

---------------------------------------------------------
Title: Complex Lines in the Spectrum of RW Cephei.
Authors: Merrill, Paul W.; Wilson, Olin C.
1956ApJ...123..392M    Altcode:
  The spectrum of this extreme supergiant M-type star observed with
  dispersion of 9 A/mm shows many absorption lines apparently with
  two components separated by a narrow central maximum. The maximum is
  probably actual emission superposed on an absorption line considerably
  widened by turbulence. In certain lines, especially the resonance
  lines of Ca i, Cr i, Mn 1, and Sr ii, the shortward component is
  greatly reinforced by the absorption of an upper expanding shell
  of gas. Shortward of X 4000 A there appear numerous narrow emission
  lines, chiefly of Fe i and Ti 1, without accompanying dark lines. The
  peculiar relative intensities of these lines are probably due to strong
  differential . The spectrum is compared with that of a Orionis.

---------------------------------------------------------
Title: The Radial Velocity of DQ Cephei = HD 199908.
Authors: Sahade, J.; Struve, O.; Wilson, O. C.; Zebergs, V.
1956ApJ...123..399S    Altcode:
  The radial velocities measured on 215 spectrograms taken on sixteen
  nights confirm Walker's photoelectric period of 0.0788650 day. The
  mean velocity of the star is - 21 9 km/sec. There is a beat period of
  0.3751 day. The total range of the principal oscillation is 9.2 km/sec;
  that of the interfering oscillation is 2.6 km/sec. The period of the
  interfering oscillation is 0 06516 or 0.09986 day. The spectrum is
  approximately Fl IV-V. The maximum brightness occurs halfway on the
  descending branch of the velocity- curve. Near minimum radial velocity
  a narrow space of continuous spectrum is visible between Ca H and
  HE. This feature is absent at other phases.

---------------------------------------------------------
Title: Award of the Bruce Gold Medal to Dr. Albrecht Unsöld
Authors: Wilson, O. C.
1956PASP...68...89W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The Possible Occurrence of λ5876 of He I in Absorption in
    the Spectra of Certain Late-Type Stars
Authors: Wilson, O. C.; Aly, M. K.
1956PASP...68..149W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The Award of the Bruce Gold Medal to Dr. Walter Baade
Authors: Wilson, O. C.
1955PASP...67...57W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Introductory remarks: THE ATMOSPHERES OF GIANT AND SUPERGIANT
    STARS
Authors: Wilson, O. C.
1955stat.conf..147W    Altcode: 1954stat.conf..147W
  No abstract at ADS

---------------------------------------------------------
Title: Chromospheric Structure of the K-Type Component of Zeta
    Aurigae.
Authors: Wilson, O. C.; Abt, Helmut A.
1954ApJS....1....1W    Altcode:
  Spectrograms of 10 A/mm dispersion taken during the 1947-1948 eclipse
  have been measured for line intensities and for radial velocities,
  and the results are compared with those obtained previously for the
  1939-1940 eclipse. Egress of 1947-1948 is found to he quite similar
  to ingress and egress of 1939-1940; ingress at the more recent eclipse
  differs, however, from the other three transits in the direction of a
  considerably slower gradient, particularly at the greater chromospheric
  heights. This effect is found from lines of all types. However,
  ingress of 1947-1948 is not distinguishable from the other transits in
  the values of any of the derived parameters: excitation temperature,
  turbulent velocity, or degree of ionization. It is shown that the
  apparent rise of AXD with height found in 1939-1940 is really due
  to a systematic difference in this quantity between the neutral and
  ionized lines. Ions indicate slightly higher turbulent velocities than
  do neutral atoms. The excitation temperature increases with height at
  about the same rate as indicated by the earlier results. Ionization
  in the chromosphere is studied in some detail, and 's theory of the
  penetration of ionizing radiation from the B star into the chromosphere
  of the K star is applied to the roblem. The outcome is that it appears
  impossible to account for the spectroscopic phenomena on t e basis
  of a smooth distribution of the chromospheric material. In fact,
  it is necessary to assume that the matter occurs in condensations of
  rather small size (thickness of the order of 10 km) and high density
  (log n[H] = 13.8) in order to keep the ionization at the required level
  and to avoid discordance with the solar abundance ratios. The model
  is in accord with all but one of the observed spectroscopic features,
  as well as with the recent interpretation of the photometric eclipse
  by Roach and Wood.

---------------------------------------------------------
Title: Spectrophotometry of the Central Stars of Four Planetary
    Nebulae.
Authors: Aller, L. H.; Wilson, O. C.
1954ApJ...119..243A    Altcode:
  An analysis of coud spectrograms of the nuclei of four planetary nebulae
  with predoininanily absorption spectra, viz., IC 418, IC 2149, NGC 2392,
  and IC 4593, yields spectral classes of on R. M. Petrie's system. The
  proffles of the hydrogen lines are compared with those of the O9 star
  10 Lacertae. Electron densities somewhat lower than those previously
  obtained for other planetary nuclei with absorption4ine spectra seem
  to be indicated. It is suggested that the He/H ratio can be greater in
  the planetary nuclei than in normal 0 stars and that the excitation
  temperatures can be systematically lower than those derived from
  Petrie's scale. A final decision will requlre a much more detailed
  analysis, involving the calculation of model atmospheres.

---------------------------------------------------------
Title: The Mass of the Globular Cluster M92.
Authors: Wilson, O. C.; Coffeen, Mary F.
1954ApJ...119..197W    Altcode:
  Radial-velocity measurements of 23 spectrograms of 15 red giant stars
  in M92 are discussed. A mass of 3.3 X t 0 is derived for the cluster,
  and the corresponding mass-to-luminosity ratio is 2.0 in solar units. It
  is probable that there are intrinsic velocity variations in some of
  the cluster stars.

---------------------------------------------------------
Title: Some Remarks on the Spatial and Kinematic Structure of the
    Planetary Nebula IC 418.
Authors: Wilson, O. C.
1953ApJ...117..264W    Altcode:
  Recent high-dispersion spectrograms have resolved the [N ii] and [0 llJ
  lines in this nebula which had appeared single with the lower dispersion
  previously used. On collecting and discussing the kinematic data for
  this low-excitation nebula and correlating them with the results from
  slitless spectrograms, it becomes highly probable that IC 418 is built
  upon the same spatiokinematic model as are the high-excitation ring
  nebulae. A brief consideration of ring nebulae in general leads to two
  alternative explanations for them: (1) If the density inside the shell
  is higher than the density in the shell, then the flow of matter is from
  the inner mass into the shell. In this case the electron temperature in
  the inner mass must be much higher than that in the shell. (2) If, on
  the other hand, the inner mass consists of matter expelled inward from
  the shell, a relatively higher density in the shell, as compared to the
  interior, is adequate to account for the appearance of the ring nebulae.

---------------------------------------------------------
Title: Monochromatic isophotic contours of planetary nebulae.
Authors: Wilson, O. C.; Aller, L. H.
1953AJ.....58R.235W    Altcode:
  Slitless spectrograms of a number of bright planetary nebulae including
  NGC 1535, 2392, 2440, 6210, 6752, 6741, 7009, 7662, and tC 418, 4593
  were obtained with the coude' spectrograph and image rotator at the
  100-inch telescope. Monochromatic images of EOIII~, LNe~IIj, ENevJ, Hei,
  Heii, and H have been analyzed with the balanced-beam isophotometer
  invented by Hiltner and Williams. A comparison of results secured by
  tal~ing successive tracings across the image with the isophotic contours
  traced by the machine showed good agreement. The greatest inacctiracy
  in the contours is introduced by internal motions in the nebula which
  prodtice a distortion of the slitless images. Direct photographs
  obtained with suitable plate and filter combinations can overcome this
  difficulty. Observations obtained with the multislit, which gives not
  only the velocities of the forward and backward sides of the shell in
  the line of sight, but also the relative amounts of material in the
  two sides of the shell, may be combined with the isophotic contour
  data to calculate three-dimensional models of some of the more regular
  nebulae. When multislit data are not available, assumptions about the
  symmetry of the nebula must be made. The contours obtained illustrate
  single and double ring structures, single nuclear and binuclear
  strticttires, as well as somewhat irregular objects. Observatory,
  University of Michigan, Ann Arbor, Mich.

---------------------------------------------------------
Title: The Structure of the Planetary Nebula IC 418.
Authors: Wilson, O. C.; Aller, Lawrence H.
1951ApJ...114..421W    Altcode:
  Slitless coude' spectrograms of the small, low-excitation, planetary
  nebula IC 418 are analyzed to determine the intensity distribution
  across the disk in various monochromatic images. From an analysis
  of these intensity distributions an attempt is made to find the
  emission per unit volume. The emission in ergs/cm3/sec is expressed
  in c.g.s. units, and the approximate ionic densities of H, He, N IT,
  0 II, 0 III, Ne iii and Sir are derived.

---------------------------------------------------------
Title: The Of-Type Spectroscopic Binary BD+40°4220.
Authors: Wilson, O. C.; Abt, Arthur
1951ApJ...114..477W    Altcode:
  The components of the spectroscopic binary BD+ are of spectral types
  Of and 09 and the period is 6.600 + 0.002 days. The mass of the 09
  star (probably a giant or supergiant) is about four times that of the
  Of. Rather pronounced periodic variations in visibility of some of
  the spectral features are briefly discussed.

---------------------------------------------------------
Title: The structural features of certain planetary nebulae.
Authors: Aller, Lawrence H.; Wilson, Olin C.
1950AJ.....55...70A    Altcode:
  Guided slitless spectrograms obtained with the aid of an image
  rotator at the coude' focus of the 100-inch reflector are used for a
  study of the structure of NGC 6572 and NGC 7662. The outer portions
  of NGC 6572 possess an amorphous structure. The nebula is not at
  all elliptically symmetrical as earlier observations with smaller
  telescopes indicated. Mg I X457I and S ii show a shell structure,
  whereas N iii X4640 and A iv X4740 apparently do not. The intensity
  distribution across the nebula, corrected for bad seeing and guiding,
  has been obtained for lines of hydrogen and helium. Isophotal contours
  of 0 iii X4959, Ne iii X3865, Hp, and Heii X4686 in NGC7662 have
  been drawn. The two forbidden lines show similar contours whereas the
  distribution of H and He ii is similar in the inner portions of the
  nebula. A three-night exposure shows that He ii does not appear in the
  outer shell at all. On the assumption that the structure of the nebula,
  in the first approximation, can be represented as circularly symmetrical
  in the plane containing the major axis of the ring and the observer,
  the radial emission distribution is derived by a method employed by
  Wallenquist in his study of star clusters. The hydrogen and Ne iii
  shells appear to be hollow, whereas there is some suggestion that
  He ii emission appears within the inner shell. Similar studies are
  in progress for other planetary nebulae, among them XGC62Io, 7009,
  and IC 418 and 4543. Observatory, University of Michigan, Ann Arbor,
  Mich. and Mt. Wilson and Palomar Observatories, Pasadena, Ca 1sf.

---------------------------------------------------------
Title: A Survey of Internal Motions in the Planetary Nebulae.
Authors: Wilson, O. C.
1950ApJ...111..279W    Altcode:
  Slit spectrograms (dispersion 10 A/mm) of twenty-six bright planetary
  nebulae have been obtained with the coude' spectrograph of the 100-inch
  telescope. For thirteen of the nebulae, slitiess spectrograms have
  been secured with the same instrument. he main observational results
  are the separations of the components of the double nebular lines
  and the dimensions of corresponding slitless images. Analysis of
  these data leads to the following principal conclusions: 1. There
  is no correlation between the relative intensities (V/R) of the red
  and violet components of the nebular lines and the general level
  of nebular excitation. 2. The number of nebulae with V/R&gt; 1 is
  about equal to the number with V/R &lt; 1; hence the nebulae are
  probably transparent in the observed wave4ength range. 3. The most
  reliable measure of expansion velocity is shown to be the mean of
  the values given by lines of H, [0 ni], and [Ne in]. There may be a
  very weak positive correlation between this quantity and the level
  of excitation. 4. Where differences in component separation exist
  in the spectrum of a planetary nebula (and they are quite common),
  tife particles show smaller separations than the low-excitation
  particles. Extreme examples are [Ne v], for which the separations
  are often close to zero, and [0 n] and [N n], which sometimes show
  large separations. Hydrogen presents an outstanding exception to the
  general run of separation with excitation, agreeing closely with [0 in]
  and [Ne in]. Available evidence is against any marked dependence of
  component separation upon transition probability. 5. There is generally
  a positive correlation between component separation and monochromatic
  image size. Usually, though not always, differences in image size are
  much less than differences in separation. 6. Components of the nebular
  lines are often quite sharp, their apparent width being frequently
  determined by the resolving power of the emulsion; but components
  of H lines are noticeably diffuse in all nebulae. By-products of the
  investigation include improved wave lengths of twenty nebular lines and
  radial velocities of twelve nebulae. Two models have been investigated
  in attempting to explain the observations. The basic assumption of
  the first model is that the velocity given by the lines of any ion
  is a measure of the velocity of the abundant H and He in the region
  where the lines in question are produced. In this model the material
  is supposed to have originally a velocity equal to that measured for
  [Ne v], which is, in some nebulae, probably less than 5 km/sec. The
  increments in velocity between [Ne v] and He ii and between He ii and
  H are assumed to be due to the increases in momentum flux carried by
  the gas upon absorption of nuclear radiation below x 228 A and between
  x 912 and x 228 A, respectively. Reasonable values of the radius and
  temperature of the central star lead, on this model, to the correct
  orders of magnitude both for the velocity changes and for the total
  nebular brightness. The second model assumes that measured velocity
  differences are due to selective forces acting upon some of the rare
  ions and maintaining them in relative motion with respect to the
  abundant H and He. It appears possible in this fashion to construct
  a model which can account for the [Ne v] anomaly on the basis of an
  inward flux of Lyman continuum from the bright hydrogen shell. This
  model leads, however, to nebulae about 5 mag. too faint, and for this
  reason the first one seems preferable.

---------------------------------------------------------
Title: Planetary Nebulae
Authors: Wilson, Olin C.
1950ASPL....6...20W    Altcode: 1950ASPL..253.....W
  No abstract at ADS

---------------------------------------------------------
Title: Proportionality of Nebular Red Shifts to Wave Length
Authors: Wilson, O. C.
1949PASP...61..132W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The Wolf-Rayet Spectroscopic Binary HD 190918.
Authors: Wilson, O. C.
1949ApJ...109...76W    Altcode:
  The emission and absorption components of this star are of types
  close to WN5 and BO, respectively. Many observations made in 1946,
  1947, and 1948 have been combined by graphical methods to yield ap-
  proximate spectrographic orbits. Only the X 4686 band of Heii was
  measured in the W spectrum, while five or six absorption lines due
  to the B-type component were regularly used. Derived constants of the
  system are: YB = -21.8 km/sec, KB = 10.0 km/sec; ~yw = -f 88 km/sec,
  K~ = 38 km/sec; (mB -f mw) sin3 i = 0.986 0. Since the spectra of the
  components of HD 190918 are not very different from those of HD 193576,
  whose minimum total masses are 35 0, it is probable that the value
  of i for HD 190918 does not exceed 18°. It is concluded, therefore,
  that the red shift of the X 4686 He ii band in WN stars is probably
  inde- pendent of the orientation of the polar axes of the stars with
  respect to the line of sight and that its origin is to be sought in
  processes occurring within the WN atmospheres

---------------------------------------------------------
Title: Book Review: Centennial Symposia, December, 1946
Authors: Wilson, O. C.
1949PA.....57...48W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: No. 755. The Wolf-Rayet spectroscopic binary HD 190918.
Authors: Wilson, O. C.
1949CMWCI.755....1W    Altcode: 1949QB4.M93n755....
  No abstract at ADS

---------------------------------------------------------
Title: Three Interesting Spectroscopic Binaries
Authors: Wilson, O. C.
1948PASP...60..385W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Variations in the Spectrum of the Wolf-Rayet Star HD 50896
Authors: Wilson, O. C.
1948PASP...60..383W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Nova Serpentis 1948
Authors: Wilson, O. C.
1948PASP...60..327W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The Nuclear and Nebular Spectra of the Planetary Nebula
    NGC 2392.
Authors: Wilson, O. C.
1948ApJ...108..201W    Altcode:
  Eighteen stellar absorption lines and three wide emission lines
  were measured on an excellent spectro- gram of the nucleus of NGC
  2392. Seven nebular lines also were measured. The two nebular lines of
  [Ne vi, X 3346 and X 3426, are single and nearly monochromatic. Other
  nebular lines are double, with a separation of about 100 km/sec between
  the components. Radial velocities of the system given by the single
  [Ne vi lines, by means of the components of the double nebular lines,
  and by the stellar emission lines are, respectively, +70.8, +71.1, and
  +70.9 km/sec. When the stellar absorption lines are grouped according
  to total excitation requirements, it is found that those of highest
  excitation (N iv) give approximately the velocity of the system. Lines
  of lower ex- citation show progressively larger displacements toward
  the violet. The lines of lowest excitation (H) yield a velocity of +45
  km/sec. These results indicate a variation of outward velocity with
  depth in the atmosphere of the nuclear star such that the N iv lines
  are formed at the greatest depth, those of H at the least depth. The
  single nebular lines of [Ne v} are unexplained. A slitless spectrogram
  indicates that these lines, as well as the double lines of [Ne m},
  [011], etc., are all formed in the inner nebular ring. Some of the
  obvious problems raised by these observations are mentioned

---------------------------------------------------------
Title: The Nuclear and Nebular Spectra of the Planetary Nebula
    NGC 2392
Authors: Wilson, Olin C.
1948PASP...60..247W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: A Preliminary Lower Limit to the Ratio
    C<SUP>12</SUP>/C<SUP>13</SUP> in Interstellar Matter
Authors: Wilson, O. C.
1948PASP...60..198W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The Structure of the Atmosphere of the K-Type Component of
    Zeta Aurigae.
Authors: Wilson, O. C.
1948ApJ...107..126W    Altcode:
  This investigation is based upon spectrograms of 10.4 A/mm dispersion
  obtained during the 1939- 1940 eclipse. * Curves of growth were
  constructed for four atmospheric levels observed during ingress and for
  three during egress. Relative gf-values for Fe I lines were taken from
  the laboratory data of King and King. For other elements the relative
  gf's were calculated from the measures of lines in the solar-flash
  spectrum made by H. H. Lane. Doppler widths, L~XD, of the theoretical
  curves of growth which best fit the observations, range from 0.08 A
  for a height above the limb of 0.8 X 106 km to 0.16 A for a height
  of 20.6 X 1O°km, with cor- responding turbulent velocities of 6.5
  and 13.0 km/sec, respectively. It appears, therefore, that the turbu-
  lence increases with height in theatmosphere. Excitation temperatures
  determined by comparison of the populations of the a~F and a3F states of
  Fe i with that of the ground state, a5D, also increase with height. Mean
  values range from 37800 at h = 0.8 X 106 km to 5660° at Ii = 13.5)&lt;
  10~ km. Density gradients in the atmosphere are readily evaluated by
  means of the curves of growth. For all atomic and ionic states included
  in this investigation the gradients are steepest at the lowest levels
  and tend to become less steep with increasing height. Moreover, except
  for Ca i in the lowest level, all the density gradients are nearly the
  same. If the densities are expressed as a function of height by means
  of the formula n = noe~, the observations yield a mean value of a = 2.3
  X 1012 cm'. The observed gradient is compared with those calculated on
  the assumption of hydrostatic equilibrium. The latter hypothesis leads
  to gradients of the order of twenty times larger than observed for
  H to one thousand times larger for Fe and elements of similar atomic
  weight. McCrea's theory of turbulent support is also investigated. If
  the turbulent velocities obtained from the curves of growth are used
  in McCrea's equa- tion, the resulting gradient is still about ten
  times too large. It cannot be decided at the present time whether this
  discrepancy is real or due to an accumulation of errors in the data. The
  ionization in the atmosphere of the K-type component is investigated,
  chiefly at heights of 7 X 10~ km and 14 X 1O~ km, for which the data
  appear most reliable. Thermodynamic equilibrium is first assumed; the
  combination of the Boltzmann and Saha equations for H, together with
  the standard ionization equation for Ca, then permit an evaluation of
  the temperature, T. The latter is found to be nearly the same as that
  of the K-type star itself, and the electron density at height 7 X 10~
  km is 1O~ per cm3, on the assumption that hydrogen supplies effectively
  all the electrons. It is next assumed that the ionization of Ca is
  governed by the dilute radiation of the B-type star and Pannekoek's
  equation is applied. It is shown that the observed ionization of Ca
  requires a higher electron density than appears to be available for H,
  and hence it is unlikely that the B-type star is responsible for the
  ionization of Ca and atoms of similar I.P. This conclusion leads to an
  investigation of the opacity of the atmosphere of the K-type star as a
  function of wave length. Menzel's opacity formula is shown to provide
  ample opacity at X «= 2000 A to screen most of the atmosphere from the
  ionizing radiation of the companion, while still insuring transparency
  in the regions ordinarily observed. On the basis of the same equation
  it is suggested that the eclipses may begin appreciably earlier in the
  ultraviolet than in the ordinary photo- graphic region. A tentative
  explanation of the rise of excitation temperature with height is based
  upon the metastability of the atomic states concerned and the variation
  of atmospheric opacity with height and wave length. INTRODUCTIO

---------------------------------------------------------
Title: No. 749. The nuclear and nebular spectra of the planetary
    nebula NGC 2392.
Authors: Wilson, O. C.
1948CMWCI.749....1W    Altcode: 1948QB4.M93n749....
  No abstract at ADS

---------------------------------------------------------
Title: No. 742. The structure of the atmosphereof the K-type component
    of Zeta Aurigae.
Authors: Wilson, O. C.
1948CMWCI.742....1W    Altcode: 1948QB4.M93n742....
  No abstract at ADS

---------------------------------------------------------
Title: Components of Interstellar Sodium Lines
Authors: Merrill, Paul W.; Wilson, O. C.
1947PASP...59..132M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Spectrum of the Planetary Nebula NGC 3242
Authors: Wilson, O. C.
1946PASP...58..210W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Absolute Dimensions of a Wolf-Rayet Star and the
    Expanding-Envelope Hypothesis.
Authors: Wilson, O. C.
1942ApJ....95..402W    Altcode:
  Measures of the equivalent width of the Hy absorption line of the
  B-type component of RD 193576 have been made during and outside
  of eclipse. These data, combined with a preliminary unpublished
  light-curve by G. E. Kron and the spectrographic orbit by the writer,
  permit the derivation of the abso- lute dimensions of the system with
  fair accuracy. It is found that the Woif-Rayet star is the larger and
  brighter of the pair, although it has the smaller mass, and Gaposchkin
  has shown it to have the smaller surface brightness. The hypothesis
  that the Woif-Rayet emission bands are formed in an expanding envelope
  surrounding the star is discussed critically. Arguments based upon
  observations, although not decisive, tend to throw doubt on the validity
  of the hypothesis. The binary character of HD 193576 offers a means of
  deciding whether or not the emission bands of the Woif-Rayet component
  are produced in an expanding envelope. In view of the facts that the
  band width corresponds to an ejection velocity of 2000 km/sec and that
  the character of the Woif-Rayet spectrum is not seriously modified by
  the presence of the companion, it is assumed that the ejected particles
  follow linear trajectories. As a consequence of this assumption,
  the radial velocity measured by the displacement of the emission
  band must differ from the true radial velocity of the star. The chief
  consequence of this transit-time effect is a difference between the
  observed times of eclipse and the times predicted by the spectrographic
  orbit. Formulae are derived from the transit-time effect and computa-
  tions of its magnitude are made for three velocity distributions and for
  a variety of inner and outer radii of the envelope, with the aid of the
  absolute dimensions of the system derived in section I. Similar com-
  putations are made of the magnitude of the violet shift of the bands
  due to occultation. The existing observations limit the difference
  between the observed and the computed times of eclipse to O.O1P, which
  requires that the supposed envelope be so small as to lead to violet
  shifts of some hundreds of km/sec. Since such shifts are not observed,
  it is concluded that the emission bands are probably not formed in
  an expanding envelope. The measured intensities of the X 4686 band of
  He ix are investigated as a function of phase. The intensity is very
  nearly the same at phases 0.25, 0.50, and 0.75, but the band is about
  19 per cent weaker at primary minimum. Perhaps there is a "reflection
  effect," which causes the Woif-Rayet star to radiate more strongly
  in the X 4686 band from the hemisphere facing the companion. A few
  tentative remarks are made concerning possible alternatives to the
  expanding-envelope hy- pothesis, although no satisfactory solution
  is found. A zone of turbulence might be invoked to account for the
  great widths of the emission bands. This explanation, however, leads
  to difficulties with the dis- placed absorption components sometimes
  observed in Woif-Rayet spectra. Moreover, it leaves unex- plained the
  red shift of the bands in HD 193576 and their periodic changes in shape

---------------------------------------------------------
Title: No. 660. Absolute dimensions of a Wolf-Rayet star and the
    expanding-envelope hypothesis.
Authors: Wilson, O. C.
1942CMWCI.660....1W    Altcode: 1942QB4.M93n660....
  No abstract at ADS

---------------------------------------------------------
Title: Three Wolf-Rayet Spectroscopic Binaries
Authors: Wilson, O. C.
1941PASP...53..295W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Some Results from the 1939-40 Eclipse of ζ Aurigae
Authors: Wilson, O. C.
1941PASP...53..228W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Narrow Lines in the Spectrum of γ Cassiopeiae
Authors: Merrill, Paul W.; Wilson, O. C.
1941PASP...53..125M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: On the Determination of Mass Ratios of Spectroscopic Binaries.
Authors: Wilson, O. C.
1941ApJ....93...29W    Altcode:
  A method is described which permits the determination of the mass
  ratio and systemic velocity of a double-lined spectroscopic binary
  from much less observational material than that required for a com-
  plete orbit determination

---------------------------------------------------------
Title: Narrow lines in the spectrum of gamma Cassiopeiae.
Authors: Merrill, P. W.; Wilson, O. C.
1941PASP...53R.125M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: No. 640. On the determination of mass ratios of spectroscopic
    binaries.
Authors: Wilson, O. C.
1941CMWCI.640....1W    Altcode: 1941QB4.M93n640....
  No abstract at ADS

---------------------------------------------------------
Title: A Wolf-Rayet Visual Binary
Authors: Wilson, O. C.
1940PASP...52..404W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Physical Characteristics of the Wolf-Rayet Stars.
Authors: Wilson, O. C.
1940ApJ....91..394W    Altcode:
  The red shift of the emission bands of the Woif-Rayet component
  of HD 193576, noted in the preceding Con1ri&amp;ut~on, suggests
  that similar displacements may be a com- mon feature of Woif-Rayet
  spectra. Examination of the wave lengths derived by Beals from measures
  of a number of Woif-Rayet stars lends strong support to this view,
  at least for stars of the nitrogen sequence. A discussion of the
  possible origins of such a shift leads to the conclusion that only
  two of them are at all likely. One of these possi- bilities, namely,
  that the red shift is due to a weakening of the violet sides of the
  bands by absorption of the light of the central star in the expanding
  envelope, does not require any modification of the current view as to
  the nature of a Woif-Rayet star. The other possible interpretation
  is that the observed displacements represent a gravitational red
  shift. If the latter is correct, the radii of the gaseous envelopes in
  which the emission bands arise cannot exceed approximately one-tenth
  that of the sun, and the nuclei themselves must be considerably
  smaller and extremely dense. Some elementary com- putations of the
  physical conditions in these small gaseous envelopes do not lead
  to any inherent impossibilities. The one grave objection appears to
  lie in the extraordinarily high surface temperatures demanded of the
  nuclei in order to produce the observed continuous spectra. In fact,
  it is suggested that, if the gravitational interpretation is adopted,
  the continuous spectra cannot be the black-body radiations of the
  nuclei at all but must be fluorescent spectra arising in the inner
  portions of the gaseous envelopes. The data available at present are
  insufficient to decide between the two possible interpretations of
  the red shift. It may only be said that the absorption explanation
  does not receive much support, since visual inspection of spectrograms
  indicates that absorption components on the violet edges of He u bands
  are quite rare. Probably careful photometric investigation of the
  contours of emission bands in Woif-Rayet spectra wifi, in the future,
  decide the question

---------------------------------------------------------
Title: The Wolf-Rayet Spectroscopic Binary HD 193576.
Authors: Wilson, O. C.
1940ApJ....91..379W    Altcode:
  Spectrographic orbits have been derived for the double-lined binary
  HP 193576. The Woff-Rayet component is of type WN5, while that of the
  absorption-line com- ponent is somewhat uncertainly estimated as Bi. The
  minimum masses of the Wolf- Rayet and B-type components are 9.740 and
  24.80, respectively. A curious feature of the results is that the y-axes
  for the two stars differ by 90 km/sec, the two values being +56 and -34
  km/sec, respectively, for the Woif-Rayet and the B components. Neither
  erroneous wave lengths nor blends seem to afford an explanation of
  this difference. Since a velocity for the system of -~4 km/sec is much
  more in keeping with the velocities of other early-type stars in the
  vicinity of HD 193576 than is one of +56 km/sec, it is probable that
  the emission bands of the Woif-Rayet star are shifted toward the red
  by an amount equal to the difference between the y-axes. The nature
  of the red shift is discussed in the following Contribution. The
  significance of certain rather minor periodic variations in the He Ii
  4686 band is discussed. In particular, no evidence for an eclipse is
  found in the spectrographic ma- terial, and, therefore, no est mate of
  the inclination of the orbit plane is possible. The absolute magnitude
  of the system has been previously derived from the intensi- ties of
  the interstellar H and K lines. It is found necessary to assume the
  stars to be 1-2 mag. brighter in order to bring the density of the
  B-type component into line with the known densities of other massive
  stars of early type. When this is done, the density of the Woif-Rayet
  star is found to be of the same order as that of the sun, if it has
  a surface temperature of 8o,ooo°. Also, the Woif-Rayet star appears
  to be about 4 mag. brighter than would be estimated from its mass on
  the basis of the empirical mass-luminosity relation

---------------------------------------------------------
Title: Relative Populations of 2^{1}S and 2^{3}S States of Helium
    in the Orion Nebula.
Authors: Wilson, O. C.
1940ApJ....91..360W    Altcode:
  The observed equivalent width of X 3889 of He i produced by the Orion
  nebula, together with the absence of X 3965, leads to a lower limit
  for the ratio of populations of the 2~S and 2'S states of N3/Ni »=
  25. This is considerably in excess of the values calculated by Struve
  and Wurm on the assumption of strict metastabifity for both levels,
  and thus points toward a shorter mean life for 2'S than for 2~S. The
  matter may be complicated, however, by the selective absorption by
  the nebula of the light from the Trapezium stars

---------------------------------------------------------
Title: No. 623. The Wolf-Rayet spectroscopic binary HD 193576.
Authors: Wilson, O. C.
1940CMWCI.623....1W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: No. 625. Relative populations of 2<SUP>1</SUP>S and
    2<SUP>3</SUP>S states of Helium in the Orion Nebula.
Authors: Wilson, O. C.
1940CMWCI.625....1W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The Wolf-Rayet spectroscopic binary HD 193576.
Authors: Wilson, Olin Chaddock
1940wrsb.book.....W    Altcode: 1940QB4.M93........
  No abstract at ADS

---------------------------------------------------------
Title: No. 624. Physical characteristics of the Wolf-Rayet stars.
Authors: Wilson, O. C.
1940CMWCI.624....1W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Possible Applications of Supernovae to the Study of the
    Nebular Red Shifts.
Authors: Wilson, O. C.
1939ApJ....90..634W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Intercomparison of Doublet Ratio and Line Intensity for
    Interstellar Sodium and Calcium.
Authors: Wilson, O. C.
1939ApJ....90..244W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: On the Doublet Ratio of Interstellar H and K and the Absolute
    Magnitudes of Wolf-Rayet Stars.
Authors: Sanford, Roscoe F.; Wilson, O. C.
1939ApJ....90..235S    Altcode:
  Observations-The total absorptions of the interstellar Ca ii lines,
  H and K, have been measured in 400 and B stars with weak H and in i8
  Woif-Rayet stars (Table i). The difficulty so often encountered in
  measuring the total absorption of H in the pres- ence of strong He
  in absorption has therefore been largely obviated, and it is hoped
  that these measures are an improvement upon earlier ones. Ratio of K
  to H-K/H appears to be approximately 2 for very weak lines and to de-
  crease, on the average, as lines of greater strength are considered,
  reaching 1.56 for H 0.4 A, with little apparent tendency to diminish
  thereafter. See Figures i and 2. Ratios D2/K and Di/H.-Twenty-f our
  stars in Table i provide measures of the total absorptions of the
  interstellar D2 and Di of Na I. The mean D2/K and Di/H derived therefrom
  are 1.63 and 2.18, respectively, which closely check earlier results,
  i.6 and the tentative value 2.1, respectively. Absolute magnitudes of
  Woif-Rayet stars-The curve which relates distance with K- line intensity
  has been used to derive the distances of the i8 Woif-Rayet stars
  from which mean visual absolute magnitudes for 6 stars of the carbon
  sequence and 12 of the nitrogen sequence have been derived. They are
  -2.8 and -2.1, respectively. Masses of the Woif-Rayet stars-Plausible
  values of temperature, together with our derived absolute magnitudes
  and what appears to be a reasonable allowance for the contribution of
  bright bands to the apparent magnitudes, give masses approximately
  thirty times that of the sun. The assumptions and guesses involved
  make such values highly speculative, even though the mass-luminosity
  relation itself is unqualifiably ac- cepted

---------------------------------------------------------
Title: No. 613. On the doublet ratio of interstellar H and K and
    the absolute magnitudes of Wolf-Rayet stars.
Authors: Sanford, Roscoe F.; Wilson, O. C.
1939CMWCI.613....1S    Altcode: 1939QB4.M93n613....
  No abstract at ADS

---------------------------------------------------------
Title: Velocities and intensities of absorption lines produced by
    helium in the Orion Nebula
Authors: Wilson, O. C.
1939PAAS....9R.274W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: No. 614. Inter comparison of doublet ratio and line intensity
    for interstellar sodium and calcium.
Authors: Wilson, O. C.
1939CMWCI.614....1W    Altcode: 1939QB4.M93n614....
  No abstract at ADS

---------------------------------------------------------
Title: Hɛ Emission in the Spectrum of Arcturus
Authors: Wilson, O. C.
1938PASP...50..245W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The Radial Velocities of 600 Stars and Measures of 69
    Spectroscopic Binaries.
Authors: Christie, William H.; Wilson, O. C.
1938ApJ....88...34C    Altcode:
  The radial velocities of 600 stars observed with the 60- and
  100-inch reflectors are given. This list is in no way homogeneous
  and contains stars from several observing lists made up for various
  investigations. In addition, measures are given for 69 variable-velocity
  stars, some of which have been observed elsewhere

---------------------------------------------------------
Title: Double Interstellar Sodium Lines
Authors: Sanford, R. F.; Merrill, P. W.; Wilson, O. C.
1938PASP...50...58S    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: No. 582. Unidentified interstellar lines in the yellow and red.
Authors: Merrill, Paul W.; Wilson, O. C.
1938CMWCI.582....1M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: No. 593. The radial velocities of 600 stars and measures of
    69 spectroscopic binaries.
Authors: Christie, William H.; Wilson, O. C.
1938CMWCI.593....1C    Altcode: 1938QB4.M93n593....
  No abstract at ADS

---------------------------------------------------------
Title: Unidentified Interstellar Lines in the Yellow and Red
Authors: Merrill, Paul W.; Wilson, O. C.
1938ApJ....87....9M    Altcode:
  Six unidentified interstellar lines (Table i) are discussed. Following
  a brief history of previous observations, Tables 2 and 3 give widths
  and central absorptions of three of the lines. The total intensity
  of X 6284, which, in the mean, equals the average for the detached
  lines Di and D2, shows a somewhat stronger correlation with stellar
  color excess than does the intensity of the D lines. The widths of the
  unidentified lines, which are rather diffuse and not sharp like the
  D lines, and other facts make an atomic origin improbable. The lines
  may be portions of molecular bands, as yet unidentified. Several facts,
  however, suggest that the lines are produced by small solid particles,
  per- haps closely related to those that cause space reddening

---------------------------------------------------------
Title: Helium Absorption Due to the Orion Nebula
Authors: Wilson, O. C.
1937PASP...49..338W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Intensities and Displacements of Interstellar Lines
Authors: Merrill, Paul W.; Sanford, Roscoe F.; Wilson, O. C.; Burwell,
   Cora G.
1937ApJ....86..274M    Altcode:
  The main purpose of this ConirThution is to record measurements of
  the intensities and displacements of the interstellar lines Di, D2, H,
  and K in the spectra of numerous early-type stars. Intensities of the
  unidentified lines XX 5780, 5797, and 6284 are in- cluded. Observational
  methods and the technique of measurement are fully described, and the
  accuracy of the results is discussed. Comparison of the Mount Wilson
  values of the intensities of the D lines with those of Beals (Table 3,
  Fig. i) indicates a fairly small accidental error in both series but
  a con- siderable systematic difference between them. Displacements
  of the D lines measured at various observatories (Table 7) are in
  good agreement. The Catalogue, Table 6, includes 254 stars brighter
  than apparent magnitude 7.0, 147 fainter stars, and, in addition,
  3 novae. The numbers of objects with the various kinds of data are
  as follows

---------------------------------------------------------
Title: Intensities of the Infrared Cα II Triplet in Stellar Spectra
Authors: Wilson, O. C.; Merrill, Paul W.
1937ApJ....86..162W    Altcode:
  The equivalent widths of the infrared Ca n triplet, XX 8498, 8542, and
  8662, have been measured on spectrograms of the sun and of several stars
  taken with a grating spectrograph having a dispersion of 33 A/mm. The
  results for the solar lines agree well with those of other observers and
  are nearly proportional to t~he square roots of the theore~ica1muitip1et
  int~nsities. In the stars, however, particularly the late-type giants,
  there is a strong tendency for the three lines to be more nearly equal
  in strength. The cause of the variation in gradient is not clear,
  and more extensive observations will be of interest

---------------------------------------------------------
Title: Forbidden Iron Lines in the Spectrum of the Companion of
    α Scorpii
Authors: Wilson, O. C.; Sanford, R. F.
1937PASP...49..221W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Analysis of the Intensities of the Interstellar D Lines
Authors: Wilson, O. C.; Merrill, Paul W.
1937ApJ....86...44W    Altcode:
  Previous investigations of interstellar lines are briefly reviewed. The
  interstellar D-line intensities measured at Mount Wilson in the spectra
  of over 200 early-type stars are critically discussed with the object of
  deducing the distribution and motions of the sodium atoms in space. If
  the atoms are assumed to have no rela- tive motions other than those
  due to temperature, the D-line intensities should follow a normal
  curve of growth. This assumption is shown to be incorrect because
  (i) the curve derived from the measured intensities does not have the
  proper shape and (2) it leads to very improbable d~istances for the
  stars with strong lines as compared to those with weak lines. The
  introduction of galactic rotation gives a good representation of
  the mean de- crease of the doublet ratio D2/DI from 2.0 to 1.2 with
  increasing intensity. A more de- tailed examination proves conclusively,
  however, that the rotational velocity gradient cannot be responsible
  for the widths of the lines because, for a given distance, the line
  intensities an~I the doublet ratio are essentially the same for all
  galactic longitudes. The observations can be accounted for by making the
  hypothesis that interstellar sodium occurs in discrete aggregations or
  clouds, which, while participating in the gen- eral galactic rotation,
  have in addition considerable random motions. This assumption requires
  no dependence upon t~ie galactic longitude and succeeds in explaining
  how the D lines can strengthen almost linearly with the distance,
  while the ratio of D 2 to Di is only 1.2. By fitting computed curves to
  the observational data, the following numerical results are obtained:
  an upper limit to the temperature is 44,000°; the density of sodium
  atoms in the ground state is approximately io-3' gm/cc; the linear
  dimensions of the clouds, in the galactic plane, are of the order of
  700 parsecs; and the spread of the ran- dom cloud velocities need not
  exceed 15 or 20 km/sec

---------------------------------------------------------
Title: The System of β Capricorni
Authors: Adams, W. S.; Sanford, R. F.; Wilson, O. C.
1937PASP...49...25A    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: No. 575. Intensities of the infrared CaII triplet in stellar
    spectra.
Authors: Wilson, O. C.; Merrill, Paul W.
1937CMWCI.575....1W    Altcode: 1937QB4.M93n575....
  No abstract at ADS

---------------------------------------------------------
Title: No. 570. Analysis of the intensities of the interstellar
    D-lines.
Authors: Wilson, O. C.; Merrill, Paul W.
1937CMWCI.570....1W    Altcode: 1937QB4.M93n570....
  No abstract at ADS

---------------------------------------------------------
Title: No. 576. Intensities and displacements of interstellar lines.
Authors: Merrill, Paul W.; Sanford, Roscoe F.; Wilson, O. C.; Burwell,
   Cora G.
1937CMWCI.576....1M    Altcode: 1937QB4.M93n576....
  No abstract at ADS

---------------------------------------------------------
Title: The Blending of H and Hɛ in the Spectrum of α Lyrae
Authors: Wilson, O. C.; Thackeray, A. D.
1936PASP...48..329W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Radial Velocity Curves of Nova Lacertae 1936
Authors: Adams, W. S.; Sanford, R. F.; Wilson, O. C.
1936PASP...48..325A    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Variations in the Spectrum of P Cygni
Authors: Wilson, O. C.
1936ApJ....84..296W    Altcode:
  An examination of spectrograms of P Cygni taken at the Lick and Mount
  Wilson observatories has shown that the Balmer lines in this star
  consist of an emission com- ponent and two absorption components,
  instead of one, as formerly supposed. These two absorption components
  vary in intensity (and probably in position) in such a way that on
  some occasions both are visible, while on others only one or the other
  is to be seen. No period for the variation can be deduced from the
  available material, but it is demonstrated that significant changes have
  occasionally occurred within intervals of the order of one month. The
  helium lines also appear to pass through a similar cycle in step with
  those of hydrogen

---------------------------------------------------------
Title: Note on the Absolute Magnitudes at Maximum of Nova Aquilae
    1918 and Nova Cygni 1920
Authors: Wilson, O. C.
1936PASP...48..229W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Distance of Nova Lacertae 1936 Derived from the Intensities
    of Interstellar Lines
Authors: Merrill, P. W.; Wilson, O. C.
1936PASP...48..230M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Contour or profile?
Authors: Wilson, O. C.; Williams, E. G.
1936Obs....59...49W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Intensities of interstellar lines
Authors: Merrill, P. W.; Wilson, O. C.
1936PAAS....8R.249M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: No. 550. Variations in the spectrum of P Cygni.
Authors: Wilson, O. C.
1936CMWCI.550....1W    Altcode: 1936QB4.M93n550....
  No abstract at ADS

---------------------------------------------------------
Title: Note on the recent eclipse of ζ Auriage
Authors: Christie, W. H.; Wilson, Olin C.
1935AN....257..183C    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Absorption Lines due to an Expanding Star
Authors: Wilson, O. C.
1935ApJ....82..233W    Altcode:
  The modification of the shape of an absorption line produced by an
  expansion or con- traction of a star is investigated. It is shown that
  Carroll's approximation is valid only for small velocities and that for
  large velocities important changes in the shape and strength of a line
  occur. Applications to giant stars and Cepheid variables are discussed
  briefly and to Woif-Rayet stars and novae with more detail. A method
  is indicated by which, if the geometrical explanation of certain
  features in the spectrum of Nova Her- culis is considered valid,
  the linear dimensions of the star may be computed. A pre- liminary
  calculation gives for the radius of the photosphere of Nova Herculis
  in its earlier stages a value of the order of iooX 106 km

---------------------------------------------------------
Title: Radial velocities from absorption lines in the spectrum of
    Nova Herculis.
Authors: Adams, W. S.; Christie, W. H.; Joy, A. H.; Sanford, R. F.;
   Wilson, O. C.
1935PASP...47..205A    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: ζ Aurigae: the Structure of a Stellar Atmosphere
Authors: Christie, William H.; Wilson, O. C.
1935ApJ....81..426C    Altcode:
  From the measures of spectrograms of ~ Aurigae taken during the 1934
  eclipse a ~iumber of new and interesting results have been obtained. By
  combining the measures of the light of the star made at Mount Wilson
  and Madi- son with the spectroscopic elements derived by Harper and
  by the authors, new ele- ments for the system have been obtained. A
  method has been devised whereby the effects of the light of the K star
  in the corn- posite spectrum of the two bodies may be eliminated from
  measures of microphotometer tracings of the spectra. This possibility
  has enabled us to measure the total absorption of the continuous
  spectrum of the B star produced by the various elements in the atmos-
  phere of the K star. From a number of microphotometer tracings made
  from the most suitable plates, the claanges in the total absorption have
  been measured for nearly a hundred lines in the spectra. These measures
  have been used to determine the effect of the B star shining through
  the atmosphere of the K star alone, thus affording means of obtaining
  the rela- tive numbers of atoms of the various elements existing at
  different levels above the photosphere of the K star. These results
  are grouped into six distinct classes: neutral metals; Mg; Ti~ (two
  groups); H; Cat Comparison of these results with theory reveals that
  there is, in most cases, no ade- quate hypothesis to account for the
  observed distribution. The measures of the bydro- gen lines indicate
  that the hydrogen shell surrounding the star is of uniform density

---------------------------------------------------------
Title: Cyanogen Absorption in the Spectrum of Nova Herculis, 1934
Authors: Wilson, O. C.; Merrill, P. W.
1935PASP...47...53W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: No. 519. &amp;Zeta Aurigae: The structure of a stellar
    atmosphere.
Authors: Christie, William H.; Wilson, O. C.
1935CMWCI.519....1C    Altcode: 1935QB4.M93n519....
  No abstract at ADS

---------------------------------------------------------
Title: Spectrophotometry of RS Ophiuchi (nova Ophiuchi no.
Authors: Wilson, O. C.; Williams, E. G.
1934ApJ....80..344W    Altcode:
  From one good plate taken with the three-prism violet spectrograph
  on August 30, 1933, the apparent color temperature of RS Ophiuchi is
  found to be 4000° K. Contours of the hydrogen emission bandshave
  been determined from several plates covering the period August
  i6-September ii, ~ On the assumption that the red sides of the bands
  present the true unmodified shapes, the following facts emerge: a)
  The contours are roughly exponential in form. The earlier ones can
  be represented approximately by the formula 1= e-(u/u~, where n-~
  r+k(uo/u)-k and k =0.125. The value u0 decreases rapidly with time
  at first, then more slowly, ftnally attaining a more or less constant
  value; k also decreases and may be considered to vanish for the later
  contours. b) In addition to a sharp absorption component present on the
  short-wave-length sides of the band maxima in the early stages, there
  appears to be a general deficiency of intensity over the violet halves
  of the bands relative to that of the red halves. The sup- position that
  this is due to the complete suppression of the continuous spectrum
  under the violet sides is not in entire agreement with the facts,
  but there may be complicating factors. This hypothesis would require
  a large velocity range among the atoms directly in front of the star,
  and leaves no room for the monochromatic hydrogen absorption components
  or for the sharp nebular lines. It is suggested that the latter arise
  in a quies- cent shell around the star left over from its previous
  outburst. The Balmer decrement has been obtained from two accordant
  plates, and is found to be appreciably faster than the mean of those
  found by Plaskett and by Berman for planetary and diffuse nebulae. The
  observed decrement is brought into good agreement with the latter by
  applying the differential factors necessary to reduce a true tempera-
  ture of 35,0000 to an apparent one of 40000. From several spectrograms
  it appears that the ratio of the area of Hy to the intensity in the
  underlying continuous spectrum did not vary greatly between August
  i6 and September 2, 1933. Zanstra's method gives a photo-electric
  temperature of 35,000°, calculated from the measures on plate V4o4,
  August i8. If this is a real measure of the temperature, it fol-
  lows from the preceding paragraph that, while the star decreased in
  brightness by about two magnitudes from August i6 to September 2, its
  temperature remained constant. This conclusion would imply that the
  fading of the star was due to a shrinkage in the radiating surface. From
  the measured intensity of the K line, with an approximate allowance for
  a probable stellar blend, a distance of 95o parsecs is deduced. This is
  shown to be fairly consistent with the recent results of Stebbins and
  Huffer on the assumption that the difference between the photo-electric
  and apparent temperatures is due to space redden- ing

---------------------------------------------------------
Title: The Analysis of Nova Emission Bands
Authors: Wilson, O. C.
1934ApJ....80..259W    Altcode:
  It is assumed, following Gerasimovi~ and Chandrasekhar, that nova
  emission bands originate in spherical expanding gaseous envelopes having
  internal velocity gradients; also that the matter in the envelope is
  transparent to its own radiation and that Chandrasekhar's occultation
  effect may be neglected. A method is then developed by which the
  velocity gradient can easily be found from the observed band shapes;
  all that is required is a simple integration. The analysis is applied
  to the hydrogen emission contours recently measured in the spectrum
  of RS Ophiuchi

---------------------------------------------------------
Title: Comparison of the Paschen and the Balmer Series of Hydrogen
    Lines in Stellar Spectra
Authors: Merrill, Paul W.; Wilson, Olin C.
1934ApJ....80...19M    Altcode:
  Introduction-The structure of the hydrogen spectrum and previous
  observations of the Paschen series are briefly described. The behavior
  of the Paschen lines m= 12 to m = 24, recently photographed at Mount
  Wilson in various types of stellar spectra, resembles in general
  that of the Bahner lines in the same types. The Paschen series is
  very conspicuous in the c stars $ Orionis and a Cygni. Photometric
  data-Measurements of structure and intensity have been made by the usual
  photometric methods on numerous lines in both hydrogen series in the
  spectra of a Leonis B8n, a Lyrae Ao, a Canis Majoris Ao, j3 Orionis
  cB8, and a Cygni cA2. Structure of lines-Most lines not affected
  by the overlapping of neighboring lines have contours of the simple
  exponential form, although in a Leonis the centers are flattened. In the
  broad-line stars a Leonis and a Lyrae considerable departure from the
  exponential form is exhibited by the wings of lines near the heads of
  the series. In ~3 On- onis, a Cygni, a Leonis, and in the emission-line
  stars `y Cassiopeiae and P Cygni the shapes of Balmer and Paschen
  lines are similar, with the dimensions proportional to wave-length;
  but this is not true of a Lyrae, in whose spectrum the Balmer lines
  have relatively more intense wings. Central intensities-Measured
  values for numerous lines are given in Table VI. In general the central
  intensities of Paschen lines are less than those of the corresponding
  Balmer lines. In a Leonis the Paschen series is relatively intense and
  has a slow decre- ment. In j3 Orionis and a Cygni both series exhibit
  slow decrements and little overlap- ping. Problem of overlapping
  lines-The shapes as well as the central intensities of many lines,
  particularly in the Balmer series, are probably seriously modified by
  the over- lapping wings of adjacent lines. The problem is to find the
  shapes and intensities of the "true" or original lines which by their
  mutual interaction produce the observed curve. A physically reasonable
  sequence of lines has been found which yields close ap- proximations
  to the observed shapes and intensities in a Lyrae but gives too great
  a reduction of the general intensity of the whole spectrum toward the
  head of the series. This difficulty, which appears to be of a rather
  general nature, is briefly discussed. Total line absorption-Measured
  values for lines of both series in a Cygni, /3 Orionis, and a Leonis
  are given in Table VII. From these data Unsold's equation gives
  the num- bers of atoms in the second and third levels. The numbers
  computed for a given level from various lines differ systematically,
  indicating that the theory is incomplete. The maximum numbers, used in
  Boltzmann's equation for thermal equilibrium, give reason- able values
  of the temperature of the absorbing hydrogen. Intensities of emission
  lines-Several bright lines in both series were measured in y Cassiopeiae
  and P Cygni. The relative importance of induced and spontaneous emis-
  sion is discussed. The photospheric temperatures computed from the
  intensities of pairs of lines having a common upper level depend on the
  assumed distribution of the atoms with respect to azimuthal quantum
  number. An assumed distribution corresponding to thermal equilibrium
  leads to reasonable temperatures for both stars. The possibility of
  determining the amount of space absorption by comparison with other
  data is pointed out. * Contributions from the Mount Wilson Observatory,
  Carnegie Institution of Washing- ton, No. 494

---------------------------------------------------------
Title: No. 501. Spectrophotometry of RS Ophiuchi (Nova Ophiuchi
    No. 3).
Authors: Wilson, O. C.; Williams, E. G.
1934CMWCI.501....1W    Altcode: 1934QB4.M93n501....
  No abstract at ADS

---------------------------------------------------------
Title: Comparison of the Balmer and Paschen series of hydrogen in
    stellar spectra
Authors: Wilson, Olin Chaddock, Jr.
1934PhDT........16W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Comparison of the Balmer and Paschen Series of Hydrogen in
    Stellar Spectra.
Authors: Wilson, Olin C.
1934PhDT.........7W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: No. 494. Comparison of the Paschen and the Balmer series of
    hydrogen lines in stellar spectra.
Authors: Merrill, Paul W.; Wilson, Olin C., Jr.
1934CMWCI.494....1M    Altcode: 1934QB4.M93n494....
  No abstract at ADS

---------------------------------------------------------
Title: No. 500. The analysis of nova emission bands.
Authors: Wilson, O. C.
1934CMWCI.500....1W    Altcode: 1934QB4.M93n500....
  No abstract at ADS

---------------------------------------------------------
Title: Contours of Absorption Lines in Nova Aquilae 1918 before
    Maximum
Authors: Wilson, O. C.
1932PASP...44..388W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: An Application of the Radiometer: a Registering Microphotometer
Authors: Smith, Sinclair; Wilson, Olin C., Jr.
1932ApJ....76..117S    Altcode:
  A registering microphotometer is described in which a radiometer is
  used as the light- sensitive element. The instrument has been made as
  simple as possible without sacrifice of performance, and tests seem
  to show that it is both fast and precise, besides being very easy to
  operate. The details of construction are discussed and some typical
  records are reproduced

---------------------------------------------------------
Title: The Velocity of Light
Authors: Wilson, Olin C.
1932Natur.130...25W    Altcode:
  IN NATURE for April 4, 1931, M. E. J. Gheury de Bray points out that
  the determinations of the velocity of light made in this century seem
  to tend towards smaller and smaller values the more recent the time
  of observation.

---------------------------------------------------------
Title: Three New Be Stars
Authors: Wilson, Olin C., Jr.
1932PASP...44..124W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: No. 454. An application of the radiometer: A registering
    microphotometer.
Authors: Smith, Sinclair; Wilson, Olin. C., Jr.
1932CMWCI.454....1S    Altcode: 1932QB4.M93n454....
  No abstract at ADS