High-resolution optical spectroscopy of a newly discovered post-AGB star with a surprising metallicity in the globular cluster M79

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ŞAHİN T., Lambert D. L.

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, cilt.398, sa.4, ss.1730-1741, 2009 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 398 Sayı: 4
  • Basım Tarihi: 2009
  • Doi Numarası: 10.1111/j.1365-2966.2009.15251.x
  • Dergi Adı: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.1730-1741
  • Anahtar Kelimeler: stars: abundances, stars: AGB and post-AGB, stars: individual: Cl*, stars: individual: M79, stars: late-type, globular clusters: individual: M79, EXPERIMENTAL OSCILLATOR-STRENGTHS, ATOMIC TRANSITION-PROBABILITIES, UBVI PHOTOMETRIC SYSTEM, SOLAR ABUNDANCE, CRITICAL COMPILATION, ASYMPTOTIC BRANCHES, CCD PHOTOMETRY, GIANT BRANCH, CR-I, PARAMETERS
  • Akdeniz Üniversitesi Adresli: Hayır

Özet

An abundance analysis based on a high-resolution spectrum is presented for a newly discovered post-asymptotic giant branch (PAGB) star in the globular cluster M79. The surprising result is that the iron abundance of the star is apparently about 0.6 dex less than that of the cluster's red giants as reported by published studies including a recent high-resolution spectroscopic analysis by Carretta and colleagues. Abundances relative to iron appear to be the same for the PAGB star and the red giants for the 15 common elements. It is suggested that the explanation for the lower abundances of the PAGB star may be that its atmospheric structure differs from that of a classical atmosphere; the temperature gradient may be flatter than predicted by a classical atmosphere.

An abundance analysis based on a high-resolution spectrum is presented for a newly discovered post-asymptotic giant branch (PAGB) star in the globular cluster M79. The surprising result is that the iron abundance of the star is apparently about 0.6 dex less than that of the cluster's red giants as reported by published studies including a recent high-resolution spectroscopic analysis by Carretta and colleagues. Abundances relative to iron appear to be the same for the PAGB star and the red giants for the 15 common elements. It is suggested that the explanation for the lower abundances of the PAGB star may be that its atmospheric structure differs from that of a classical atmosphere; the temperature gradient may be flatter than predicted by a classical atmosphere.