Lithium 6104 angstrom in population II stars

A Ford, R D Jeffries, B Smalley, S G Ryan, W Aoki, S Kawanomoto, D J James, J R Barnes

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)

Abstract

We have obtained echelle spectroscopy of 14 Population II objects selected from those previously observed by Bonifacio & Molaro (1997). For one object, HD 140283, we obtained exquisite data with the High Dispersion Spectrograph on the Subaru Telescope, with S/N exceeding 1000 per 0.018 Angstrom pixel. Li abundances have been determined by spectral synthesis from both the 6708 Angstrom resonance line and also from 6104 Angstrom subordinate feature. Firm detections of the weak line have been made in seven objects, and upper limits are reported for the remainder. Our 6708 Angstrom abundances agree with those reported by Bonifacio & Molaro with a mean difference of only 0.019 +/- 0.009 dex. Abundances from the 6104 Angstrom line hint at a higher Li abundance than that determined from the resonance feature, but this evidence is mixed; the weakness of the 6104 Angstrom line and the large number of upper limits make it difficult to draw firm conclusions. NLTE-corrections increase (rather than eliminate) the size of the (potential) discrepancy, and binarity appears unlikely to affect any abundance difference. The effect of multidimensional atmospheres on the line abundances was also considered, although it appears that use of 3-D (LTE) models could again act to increase the discrepancy, if one is indeed present.

Original languageEnglish
Pages (from-to)617-628
Number of pages12
JournalExperimental Astronomy
Volume393
DOIs
Publication statusPublished - Oct 2002

Keywords

  • stars : abundances
  • stars : Population II
  • stars : interiors
  • SOLAR-TYPE STARS
  • LI-I
  • PRIMORDIAL LITHIUM
  • PHOTOSPHERIC GRANULATION
  • SPITE PLATEAU
  • HALO-STARS
  • ABUNDANCE
  • PLEIADES
  • LINES
  • CONVECTION

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