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Astron. Astrophys. 363, L33-L36 (2000)

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Letter to the Editor

The boron absorption line at 2089.6 Å in HD 140283? *

P. Thorén and B. Edvardsson

Uppsala Astronomical Observatory, Box 515, 751 20 Uppsala, Sweden

Received 11 September 2000 / Accepted 14 November 2000


We have observed the B I line at 2089.6 Å in the metal poor star HD 140283 with HST/STIS. The observation was an attempt to confirm the B abundances derived from the 2497 Å B I line in earlier works in general, and for for this star in particular (Edvardsson et al. 1994; Kiselman & Carlsson 1996). The resulting spectrum gained from 8 orbits of observations is hardly consistent with the boron abundance derived in the earlier works. A pure 10B line could produce the feature observed but no reasonable process can produce such a ratio between 10B and 11B. More likely the analysed feature is affected by a statistical fluctuation. A conservative upper limit estimate of the NLTE corrected boron abundance gives a value marginally consistent with that derived from the 2497 Å line. We are proposing further observations to derive a more definite abundance from the line.

Key words: stars: abundances – stars: Population II – stars: individual: HD 140283 – Galaxy: abundances

* Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under contract NAS 5-26555

Send offprint requests to: Bengt Edvardsson

© European Southern Observatory (ESO) 2000

Online publication: December 5, 2000