BVR Photometry of Northern Hemisphere Luminous Stars. III. LS and HD Stars
CCD-based BVR photometry of 48 previously unobserved stars drawn fromvolumes V and VI of the Luminous Stars in the Northern Milky Way,Luminous Stars in the Southern Milky Way, and HD catalogs is reported.
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UBV beta Database for Case-Hamburg Northern and Southern Luminous Stars
A database of photoelectric UBV beta photometry for stars listed in theCase-Hamburg northern and southern Milky Way luminous stars surveys hasbeen compiled from the original research literature. Consisting of over16,000 observations of some 7300 stars from over 500 sources, thisdatabase constitutes the most complete compilation of such photometryavailable for intrinsically luminous stars around the Galactic plane.Over 5000 stars listed in the Case-Hamburg surveys still lackfundamental photometric data.
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A spectroscopic database for Stephenson-Sanduleak Southern Luminous Stars
A database of published spectral classifications for objects in theStepenson-Sanduleak Luminous Stars in the Southern Milky Way catalog hasbeen compiled from the literature. A total of 6182 classifications for2562 stars from 139 sources are incorporated.
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A new survey of nebulae around Galactic Wolf-Rayet stars in the northern sky
Interference filter CCD images have been obtained in H-alpha andforbidden O III 5007 A for 62 Wolf-Rayet (W-R) stars, representing acomplete survey of nebulae around Galactic W-R stars in the northernsky. We find probable new ring nebulae around W-R stars number 113, 116and 132, and possible new ring nebulae around W-R stars number 133 and153. All survey images showing nebulosities around W-R stars arepresented in this paper. New physical information is derived from theimproved images of known ring nebulae. The absence of ring nebulaearound most W-R stars is discussed.
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Absolute spectrophotometry of northern Wolf-Rayet stars - How similar are the colors?
Spectrophotometry of 55 Wolf-Rayet stars is presented in order todetermine the dependence of their intrinsic colors on spectral subtype.These data are the first with both sufficient photometric precision andspectral resolution to determine magnitudes and colors withoutcontamination from emission lines. It is found that the effect ofemission lines on previous ubvr filter photometry did occasionallyamount to as much as 0.3 mag in the colors. These data do not confirmearlier reports of ultraviolet excesses for WN stars, nor do theysupport the claim of differences in colors for WN and WC types. Thedifferences in the intrinsic colors of W-R stars from subtype to subtypeis small compared to the considerable variation present among stars ofthe same subtype. Despite the improved accuracy in determining thecontinuum colors, reddening-free indices still show scatter far inexcess of the observational uncertainties, particularly at shorterwavelengths.
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Galactic ring nebulae associated with Wolf-Rayet stars. VIII Summary and atlas
Photographs for ten galactic ring nebulae associated with WR stars arepresented, and references are given to published photographs for othersuch nebulae. Every WR ring nebula suggested in the literature isdiscussed and reevaluated. Fabry-Perot data have been obtained for twonew nebulae in order to diagnose their formation mechanisms. Sevenstellar wind-blown bubble type (W type), two stellar ejecta type, fourshell-structured H II region type (Rs type), and twoamorphous region type nebulae are acknowledged. Most W-type nebulae areassociated with early-type WN stars, while most Rs-typenebulae surround WC stars. The implications of statistical results forthese ring nebulae are discussed.
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The evolution of massive stars - The numbers and distribution of O stars and Wolf-Rayet stars
The Mv-spectral type calibration of the O and Wolf-Rayet (W-R) stars isreexamined. The actual numbers and distributions of stars and their W-Rdescendants in a volume-limited sample of stars within 2.5 kpc of thesun are compared. Evolutionary computations, with and without asimplified overshooting criterion for massive stars, are discussed inview of the observations in this sample. The following conclusions arereached: (1) Wolf-Rayet stars are descendant from stars with initialmasses greater than 40 solar masses; and (2) with conventional modelsand assuming continuous star formation, the observed number ratio of W-Rto Q stars is at least a factor of 3 larger than theoretically expected.This discrepancy can be lessened by taking account of the following: (1)the number and distribution of very luminous early-B supergiantssuggests that they are also core hydrogen burning objects, so that thesepredecessors to W-R stars must be counted among the O star statistics;(2) overshooting during the W-R core helium burning phase might beimportant, thus lengthening the lifetime of this phase; (3) starformation in the Galaxy, at least for the most massive stars, mightoccur in relatively short-lived bursts.
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The intrinsically bright Wolf-Rayet stars of type WN7. IV - The galactic WN7/WN8 stars as massive O-stars in advanced stages of evolution
Abstract image available at:http://adsabs.harvard.edu/abs/1979A&A....77..128M
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Stellar Spectra in Milky way Regions. VIII. a Region in Orion.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1959ApJS....4...23M&db_key=AST
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