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

Journal Article · Wed May 01 00:00:00 EDT 1991 · Astrophysical Journal; (United States)

DOI:https://doi.org/10.1086/186018· OSTI ID:5394076

Vennes, S; Shipman, H L; Thorstensen, J R; Thejll, P ^[1]

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1. Delaware, University, Newark (USA) Dartmouth College, Hanover, NH (USA) NORDITA, Copenhagen, Denmark (USA)

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.

• OSTI ID: 5394076
• Journal Information: Astrophysical Journal; (United States), Journal Name: Astrophysical Journal; (United States) Vol. 372; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
BALMER LINES
BINARY STARS
DWARF STARS
GRAVITATION
MASS
RADIAL VELOCITY
RED SHIFT
SIZE
SPECTRA
STARS
STELLAR ATMOSPHERES
STELLAR RADIATION
ULTRAVIOLET SPECTRA
VELOCITY
WHITE DWARF STARS