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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.
| UBVRI photometry and polarimetry of the stars in S 252 (NGC 2175). I. The observations.
Photoelectric UBVRI photometry and polarimetry and photographic UBVRphotometry of stars in the direction of the galactic H II regionSharpless 252 are reported
| 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.
| Spectroscopic studies of Wolf-Rayet stars. III - The WC subclass
Wolf-Rayet (W-R) stars, which are the descendants of massive O-typestars, can be subdivided into three groups depending on their spectralappearance. These groups include the nitrogen class (WN), the carbonclass (WC), and the oxygen class (WO). The present paper is concernedwith the WC stars. The assignment of WC subtypes has been based onvisual inspections of photographic plates. One of the aims of this studyis related to the quantification of the visual estimates. The measuredratios of equivalent widths and the FWHM of the 4650 A line for Galacticand LMC stars are presented, and the reclassification of some stars isproposed on this basis. In particular, it is shown that the majority ofthe LMC WC stars should logically be classified WC4 instead of WC5.Comments on individual stars are provided, and terminal velocities arediscussed. It is attempted to give a complete overview of the mostimportant spectroscopic features of the WC stars in the optical region.
| 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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