Hot stellar population synthesis from the UV spectrum: The globular cluster M79 (NGC 1904)

Jorick S. Vink, Sara R. Heap, Allen V. Sweigart, Thierry Lanz, Ivan - Hubeny

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

We have analyzed the far UV-spectrum of the globular cluster M79. We show that the nearly Gaussian mass distribution of zero-age horizontal-branch stars, as derived by Dixon et al. (1996), is able to reproduce the far-UV Hopkins Utraviolet Telescope (HUT) spectrum, if there is a luminous UV-bright star of about Teff = 9,500 K within the HUT entrance slit, or, more likely, if the horizontal branch morphology becomes considerably redder in the core of M79, as observed in some other centrally condensed globular clusters. Agreement between the synthetic and observed far-UV spectra for M79 would also be improved if the surface abundances of the heavy elements in the hot horizontal-branch stars were enhanced by radiative diffusion. Contrary to Dixon et al. (1996) we do not need extremely low gravities to reproduce the width of Ly α.

Original languageEnglish (US)
Pages (from-to)109-116
Number of pages8
JournalAstronomy and Astrophysics
Volume345
Issue number1
Publication statusPublished - 1999
Externally publishedYes

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Keywords

  • Galaxy: Globular clusters: Individual: M79
  • Stars: Evolution
  • Stars: Hertzsprung-russel (HR) and C-M diagrams
  • Stars: Horizontal-branch
  • Ultraviolet: General
  • Ultraviolet: Stars

ASJC Scopus subject areas

  • Space and Planetary Science

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