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Temperatures for Hot and Pulsating Helium-Rich (DB) White Dwarfs Obtained with the IUE Observatory

Published online by Cambridge University Press:  12 April 2016

J. Liebert ,
F. Wesemael ,
C.J. Hansen ,
G. Fontaine ,
H.L. Shipman ,
E.M. Sion ,
D.E. Winget  and
R.F. Green
J. Liebert
Affiliation:
Steward Observatory, University of Arizona.
F. Wesemael
Affiliation:
Département de Physique, Université de Montréal.
C.J. Hansen
Affiliation:
Department of Astrophysical, Planetary, and Atmospheric Sciences and JILA, University of Colorado.
G. Fontaine
Affiliation:
Département de Physique, Université de Montréal.
H.L. Shipman
Affiliation:
Department of Physics, University of Delaware.
E.M. Sion
Affiliation:
Department of Astronomy, Villanova University.
D.E. Winget
Affiliation:
Department of Astronomy and McDonald Observatory, University of Texas at Austin.
R.F. Green
Affiliation:
Kitt Peak National Observatory, NOAO.

Abstract

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Ultraviolet energy distributions are analyzed for several hot, helium atmosphere DB white dwarfs, including the four known pulsating stars which define an empirical DB instability strip. Temperatures are derived exclusively from fits to the ultraviolet energy distributions. The blue edge of the empirical DB instability strip lies at 30,000 ± 4,000 K, and the red edge lies near 24,000 ± 2,000 K. The hottest DB star — and the only known one hotter than the instability strip — is PG0112+104 at or above 30,000 K. This leaves no known helium-atmosphere degenerate stars in the interval 30,000 ≤ Te ≤ 45.000K.

Type
VII Related Objects
Information
International Astronomical Union Colloquium , Volume 87: Hydrogen Deficient Stars and Related Objects , 1985 , pp. 387 - 390
Copyright
Copyright © Reidel 1986

References

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