Hostname: page-component-848d4c4894-pjpqr Total loading time: 0 Render date: 2024-07-03T15:44:31.052Z Has data issue: false hasContentIssue false
  • English
  • Français

Helium Abundance in the Photospheres of Hot Da White Dwarfs

Published online by Cambridge University Press:  12 April 2016

J. B. Holberg ,
K. Kidder ,
J. Liebert  and
F. Wesemael
J. B. Holberg
Affiliation:
Lunar and Planetary Laboratory,University of Arizona Tucson, Arizona 85721
K. Kidder
Affiliation:
Lunar and Planetary Laboratory,University of Arizona Tucson, Arizona 85721
J. Liebert
Affiliation:
Steward Observatory,University of Arizona Tucson, Arizona 85721
F. Wesemael
Affiliation:
Département de Physique and Observatoire du,Mont Mégantic Université de Montréal

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We have used optical and UV spectroscopy to determine He abundances and upper limits to He abundances in the photospheres of a selected sample of very hot hydrogen-rich white dwarfs. He abundances in the range log(He/H) -3 to -1.5 are observed in several of these DAs and upper limits of -3 determined for the remainder. In apparent contradiction to the relatively large He abundances inferred from soft X-ray observations for the hot DA G191 B2B, we find no evidence of He in the optical and UV.

Type
Research Article
Information
International Astronomical Union Colloquium , Volume 114: White Dwarfs , 1989 , pp. 188 - 193
Copyright
Copyright © Springer-Verlag 1989

References

Fleming, T.A., Liebert, J., and Green, R.: 1986, Astrophys. J., 308, 176 (FLG).CrossRefGoogle Scholar
Fontaine, G., and Wesemael, F.: 1987, in IAU Coll. No. 95 The Second Conference on Faint Blue Stars, Philip, A.G. D., Hayes, D.S. and Liebert, J., eds., L. Davis Press, Schenectady, p. 319.Google Scholar
Griem, H.R.: 1974, Spectral line Broadening by Plasmas (New York Academic Press).Google Scholar
Holberg, J.B.: 1987, in IAU Coll. No. 95 The Second Conference on Faint Blue Stars, Philip, A.G.D., Hayes, D.S. and Liebert, J., eds., L. Davis Press, Schenectady, p. 283.Google Scholar
Holberg, J.B., Wesemael, F., and Basile, J.: 1986, Astrophys. J., 306, 629.Google Scholar
Jordan, S., Koester, D., Wulf-Mathies, C. and Brunner, H.: 1987, Astron. Astrophys., 185, 253.Google Scholar
Kahn, S.M., Wesemael, F., Liebert, J., Raymond, J.C., Steiner, J.E., and Shipman, H.: 1984, Astrophys. J., 278, 255.Google Scholar
Koester, D.: 1987, in IAU Coll. No. 95 The Second Conference on Faint Blue Stars, Philip, A.G.D., Hayes, D.S. and Liebert, J., eds., L. Davis Press, Schenectady, p. 329.Google Scholar
Liebert, J., Fontaine, G., and Wesemael, F.: 1987, Mem. Soc. Ast. Ital., 58, 17.Google Scholar
Liebert, J., et al.: 1988, in preparation.Google Scholar
Paerels, F.B.S., and Heise, J.: 1988, Astrophys. J. (in press).Google Scholar
Petre, R., Shipman, H.L., and Canizares, C.R. : 1986, Astrophys. J., 304, 356.Google Scholar
Vennes, S., Pelletier, C., Fontaine, G., and Wesemael, F.: 1988, Astrophys. J. (in press).Google Scholar
Videl, C.R., Cooper, J., and Smith, E.W.: 1973, Astrophys. J. (Suppl.), 25, 37.Google Scholar
Wesemael, F. 1981, Astrophys.J. (Suppl.): 45, 177.Google Scholar
Wesemael, F., Auer, L.H., van Horn, H.M. and Savedoff, M.P.: 1980, Astrophys. J. (Suppl.): 43, 159.Google Scholar
Wesemael, F., Liebert, J., and Green, R.F. : 1984, Publ. Astron. Soc. Pacific, 96, 981.CrossRefGoogle Scholar
Wesemael, F., Green, R.F., and Liebert, J.: 1985, Astrophys. J. (Suppl.), 58, 379.Google Scholar