Stellar Oxygen Abundances.V.Abundances of Two Hyades Dwarfs Derived from the 6300 Angstroms [OI] Line

Astronomy and Astrophysics – Astronomy

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

21

Stars: Abundances, Open Clusters And Associations: Individual: Hyades, Stars: Evolution, Stars: Interiors

Scientific paper

We present observations of the 6300 Å [O I] spectral region in two cool Hyades dwarfs, vB 79 and vB 25. We derive a mean iron abundance, [Fe/H]˜+0.11, in good agreement with recent analyses of F and G Hyades dwarfs. The O abundance derived from spectrum synthesis, [O/H]˜+0.15, is between the values deduced by Garcia Lopez et al. (1993, ApJ, 412, 173; [O/H]=-0.05 to -0.10) and King (1993, Ph. D. Dissertation, University of Hawaii; [O/H]=+0.26), who employed the 7774 Å O I triplet in hotter Hyades dwarfs. An accounting of differences between these two 7774 Å analyses is given. Our [O I]-based determination suggests the Hyades O abundance itself is super-solar, though [O/Fe]˜0.0; however, systematic errors as large as 0.10-0.15 dex cannot be ruled out. The Hyades giants show an unexpected ˜0.23 dex O deficit relative to our dwarf value. While some suggestive evidence for non-standard nuclear processing and mixing in the Hyades giants may exist, we find it unconvincing. Rather, model atmosphere deficiencies or [O I] -region blending features that are still unrecognized by laboratory and theoretical efforts may contribute to the giant-dwarf O discrepancy. Finally, our high O abundance is marginally consistent with values claimed to provide a solution to the Hyades Li problem from standard stellar models. However, it is not clear that these models do in fact reproduce the extant Li data. Our Li abundance upper limit for vB 25 is at least 0.5 dex lower than the abundances of two tidally locked binaries of similar Teff. Standard stellar models of uniform composition and age are not able to reproduce such scatter in Li.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Stellar Oxygen Abundances.V.Abundances of Two Hyades Dwarfs Derived from the 6300 Angstroms [OI] Line does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Stellar Oxygen Abundances.V.Abundances of Two Hyades Dwarfs Derived from the 6300 Angstroms [OI] Line, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stellar Oxygen Abundances.V.Abundances of Two Hyades Dwarfs Derived from the 6300 Angstroms [OI] Line will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-818975

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.