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Title: The binary Feige 24 - The mass, radius, and gravitational redshift of the DA white dwarf

Observations are reported which refine the binary ephemeris of the Feige 24 system, which contains a peculiar hot DA white dwarf and an M dwarf with an atmosphere illuminated by extreme ultraviolet radiation from the white dwarf. With the new ephemeris and a set of IUE high-dispersion spectra, showing phase-dependent redshifted C IV, N V, and Si IV resonance lines, the orbital velocity, and hence the mass (0.54 + or {minus} 0.20 solar masses), and the gravitational redshift of the white dwarf (14.1 + or {minus} 5.2 km/s) are determined independently. It is shown that the measured Einstein redshift is consistent with an estimated radius for the white dwarf obtained from a model atmosphere solid angle and a parallax measurement. This radius is twice the Hamada-Salpeter radius for the given mass and offers a prospect to investigate the presence of a massive hydrogen envelope in that white dwarf star. 27 refs.
Authors:
; ; ;  [1]
  1. (Delaware, University, Newark (USA) Dartmouth College, Hanover, NH (USA) NORDITA, Copenhagen, Denmark (USA))
Publication Date:
OSTI Identifier:
5394076
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; (United States); Journal Volume: 372; Other Information: L37-L40
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; WHITE DWARF STARS; MASS; RED SHIFT; SIZE; BALMER LINES; BINARY STARS; DWARF STARS; GRAVITATION; RADIAL VELOCITY; STELLAR ATMOSPHERES; STELLAR RADIATION; ULTRAVIOLET SPECTRA; ATMOSPHERES; SPECTRA; STARS; VELOCITY 640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar, Radio & X-Ray Sources