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An Archive of IUE Low-Dispersion Spectra of the White Dwarf Stars
We have produced an archive of the ultraviolet low-dispersion spectrafor the full set of white dwarf stars observed with the InternationalUltraviolet Explorer (IUE) satellite over the course of its 18 yrmission. This archive contains the spectra of 322 individual degeneratestars which have been processed to optimize the signal-to-noise for eachstar. In particular, all spectra have been corrected for residualtemporal and thermal effects and placed on the Hubble Space TelescopeFaint Object Spectrograph absolute flux scale using procedures describedby Massa & Fitzpatrick. Wherever possible, multiple observations ofindividual stars have been co-added to further enhance signal-to-noiseand have been combined into a single spectrum including the full 1150 to3150 Å wavelength region observed by IUE. The contents of thisspectral archive are described and the details of data reductionprocedures are provided, along with the url for access to the electronicfiles of the processed spectra.
| A Catalog of Spectroscopically Identified White Dwarfs
A catalog of 2249 white dwarfs which have been identifiedspectroscopically is presented complete through 1996 April. Thiscompilation is the fourth edition of the Villanova Catalog ofSpectroscopically Identified White Dwarfs. For each degenerate star, thefollowing data entries with references are provided: (1) a catalogcoordinate designation or WD number, in order of right ascension; (2)the right ascension and declination for epoch 1950.0; (3) the spectraltype based upon the new system; (4) a catalog symbol denoting binarymembership; (5) a list of most names known to exist for a given star;(6) proper motion and position angle; (7) broadband UBV photometry, V,B-V, U-B (8) multichannel spectrophotometry, v(MC), g-r (9)Strömgren narrowband photometry, y, b-y, u-b (10) an absolutevisual magnitude based upon the best available color-magnitudecalibration or trigonometric parallax; (11) the observed radial velocityuncorrected for gravitational redshift or solar motion; and (12) thetrigonometric parallax with mean error when available. Notes for unusualor peculiar stars and a coded Reference Key alphabetized by the firstauthor's last name are presented, as well as an expanded tablecross-referencing all names to the catalog WD number. An introductionand full descriptions of the entries are provided in the text.
| Gravitational redshift determinations for white dwarfs in common proper-motion binaries
Gravitational redshifts determined using the 5 m Hale telescope aregiven for 23 white dwarfs belonging to common proper-motion binarysystems and additional velocities are presented for 14 pairs found notto comprise physical binaries or that have unmeasurable velocities. Themass distribution for the common proper-motion pairs using thegravitational redshifts and the mass-radius relation peaks strongly near0.55 solar mass, and the main details of the shape agree with earlierdeterminations using other methods although a problem remains withcontamination with optical pairs. The redshifts and radii of a subset ofthese objects with known distances are consistent with the mass-radiusrelation for white dwarfs.
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Observation and Astrometry data
| Constellation: | Serpent |
| Right ascension: | 15h46m43.92s |
| Declination: | +00°45'25.7" |
| Apparent magnitude: | 9.867 |
| Proper motion RA: | -32.7 |
| Proper motion Dec: | 18.5 |
| B-T magnitude: | 10.397 |
| V-T magnitude: | 9.911 |
Catalogs and designations:
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