An analysis of the optical spectra of the post-asymptotic giant branch stars LSIV-12111 and HD 341617

R. S.I. Ryans, P. L. Dufton, C. J. Mooney, W. R.J. Rolleston, F. P. Keenan, I. Hubeny, T. Lanz

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Abstract

High spectral resolution and signal-to-noise observations of the absorption and emission line spectra in two post-asymptotic-giant-branch (PAGB) stellar candidates, LSIV-12111 and HD 314617 are discussed. The absorption line spectra have been analysed using non-LTE model atmosphere techniques to determine stellar atmospheric parameters and chemical compositions, both in absolute terms and relative to a standard star, HD 13841. The atmospheric parameters differ from previous estimates based on LTE model atmospheres, probably due to non-LTE effects. In turn these imply stellar masses that are generally larger than have been previously estimated. Both PAGB candidates have relative uniform underabundances of metals with mean values of -0.35 dex for LSIV-12 111 and -0.50 dex for HD 314617. Furthermore, their abundance patterns are remarkably similar to that observed for optically bright, F-type PAGBs. From the emission spectra, the plasma parameters and angular size of the circumstellar material are constrained, and these are consistent with previous estimates and with a PAGB evolutionary stage.

Original languageEnglish (US)
Pages (from-to)1119-1129
Number of pages11
JournalAstronomy and astrophysics
Volume401
Issue number3
DOIs
StatePublished - Apr 2003

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Keywords

  • Stars: abundances
  • Stars: early-type
  • Stars: fundamental parameters
  • Stars: supergiants

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Ryans, R. S. I., Dufton, P. L., Mooney, C. J., Rolleston, W. R. J., Keenan, F. P., Hubeny, I., & Lanz, T. (2003). An analysis of the optical spectra of the post-asymptotic giant branch stars LSIV-12111 and HD 341617. Astronomy and astrophysics, 401(3), 1119-1129. https://doi.org/10.1051/0004-6361:20030191