Detection of trace helium in G104 - 27, a 26,000 K DA white dwarf

Journal Article · Sat Dec 01 04:00:00 EST 1990 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/185892· OSTI ID:6261444

Holberg, J B; Kidder, K M; Wesemael, F ^[1]

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1. Arizona Univ., Tucson (USA) Montreal Universite, Montreal (Canada)

The detection of the He I 4471 A feature in the moderately hot DA white dwarf G104 - 27 places this star within the rather sparse class of DAB white dwarfs. It does not appear possible, on the basis of the present data, to distinguish between a stratified and a homogeneously mixed atmosphere. While a stratified structure would be natural for a DA white dwarf, G104 - 27 resides near the red edge of the DB gap, in a region where DA stars could transform into DB stars through convective mixing in the underlying He envelope and thereby destroy envelope stratification. Both atmospheres are consistent with the existing soft X-ray flux limit for this star. 37 refs.

• OSTI ID: 6261444
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 365; 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
ABUNDANCE
ATMOSPHERES
CHARGED PARTICLES
CHEMICAL COMPOSITION
CLASSIFICATION
DWARF STARS
ELECTROMAGNETIC RADIATION
ELEMENT ABUNDANCE
ELEMENTS
FLUIDS
GASES
HELIUM
HELIUM IONS
IONIZING RADIATIONS
IONS
MIXING
NONMETALS
RADIATIONS
RARE GASES
SOFT X RADIATION
SPECTRA
STARS
STELLAR ATMOSPHERES
STRATIFICATION
TRACE AMOUNTS
ULTRAVIOLET SPECTRA
WHITE DWARF STARS
X RADIATION