WD1987 (S0): Catalog of Spectroscopically Identified White Dwarfs (19930512)
FILE: wd1987.s0 (2220 entries covering 1279 stars)
CONTENTS: Catalog of Spectroscopically Identified White Dwarfs, 1987
DATASET: This file comes in HyperSky dataset S-15, version 19930512. Availability on HyperSky CD-ROM: Vol. 1 (1993)
DESCRIPTION: This datafile contains the third edition of the Villanova CATALOG OF SPECTROSCOPICALLY IDENTIFIED WHITE DWARFS (McCook and Sion 1987). The 1987 version succeeds the first (McCook and Sion 1977) and second (McCook and Sion 1984) editions of the catalog. The present third edition of the catalog is a compilation of 1279 white dwarfs that been identified spectroscopically up to January 1987. The HyperSky file is based on the machine-readable version of the catalog, as provided on the NASA/GSFC Astronomical Data Center (ADC) cd-rom "Selected Astronomical Catalogs", Volume 1.
The Villanova catalog contains a large amount of basic photometric and spectroscopic data (with literature references), identification cross references, and absolute visual magnitudes computed from trigonometric parallaxes or the best available color-magnitude calibrations. The HyperSky file contains a selected subset of this material, excluding any references. For these, interested users are directed to the documentaion files accompanying ADC cd-rom version of the catalog.
Because there are multiple entries (multiple references) for most of the 1279 white dwarfs, the ADC catalog contains a total of 2420 entries. Of these, the HyperSky file retains 2220 entries. The information in the excluded entries was either redundant or not used in the HyperSky file.
Because white dwarfs are intrinsically faint, catalog magnitudes range from 8.3 down to 21. Such a range presents interesting HyperSky display challenges, since even the brightest catalog white dwarfs may fall below the faint magnitude limit on normal wide-field HyperSky displays. Further, if you extend your faint magnitude limit deep enough to catch most white dwarfs, normal wide fields will be overwhelmed by large images of all the brighter stars. Hence it is not easy to scan a wide HyperSky field to quickly locate possible white dwarfs in a given area.
To solve this dilemma, a three-step approach is suggested for using this file with wide-fields in HyperSky:
1. Set your star file ("s0" file) magnitude limit appropriately for the faintest white dwarfs that interest you.
2. Use HyperSky menu options to put tickmarks on all stars in file WD1987.S0; this will make all white dwarfs much easier to spot.
3. When scanning wide fields for white dwarfs, make all other HyperSky star files INACTIVE, except for one or two small "marker" files such as BAYER.S0, which will serve to mark the brightest stars in each constellation. Re-activate your remaining star files only when you are ready to "zoom-in" your scale to take a detailed look at the small-scale field surrounding a white dwarf that interests you.
DATA: The HyperSky datafile contains the following data from the BSC4 catalog:
POSITION: Right Ascension and Declination are the catalog 1950 values, precessed to 2000. Proper motion data, though displayed in the HyperSky file, was not applied.
MAG: the catalog magnitude. This magnitude will be visual unless the string "m=pg", indicating a photographic magnitude, appears below the object identification line.
TY: is "wd", indicating "white dwarf", for every star in the catalog.
IDENTIFICATION: The WD("White Dwarf") number. This number has the general form HHmm+DDd, and represents the approximate 1950 position of the star.
COMMENTS: The comment lines contain the following information, provided if available for each entry:
* A line beginning with "=", containing identifications of the star in alternate catalogs. No explanation was provided for the various abbreviations in these names.
* The string "m=pg" (as mentioned above), indicating that the magnitude on the object identification line is photographic rather than visual.
* A string of the general form "vAbs=NN.N", giving the computed absolute magnitude of the white dwarf.
* A string of the general form "sp=Dxxx", giving the spectral class of the white dwarf.
* A string beginning with "B-V=", giving the blue-visual magnitude color index of the white dwarf. A trailing colon indicates an uncertain value.
* A string starting with "U-B=", giving the ultraviolet-blue magnitude color index of the white dwarf. A trailing colon indicates an uncertain value.
* A string starting with "RV=" giving the radial velocity in km/sec. Positive values indicate recession; negative values indicate approach.
* A string starting with "PM=" giving the annual proper motion in arc seconds. The PM value will normally be followed by a "/" and a number indicating the position angle of the proper motion (North thru East) in whole degrees.
* A string starting with "plx=", giving the trigonometric parallax of the white dwarf in arc seconds.
* At the end there may be free-form comments (eg, "ZZ CETI VARIABLE") for a small number (200) of the stars. These are condensed remarks extracted from the note file included in the ADC catalog.