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Astron. Astrophys. 332, 1017-1024 (1998)

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Boron in the very metal-poor star BD -13 3442 *

D.K. Duncan 1, 2, L.M. Rebull 1, F. Primas 1, 3, A.M. Boesgaard 4, Constantine P. Deliyannis 5, 6, L.M. Hobbs 7, J.R. King 8 and S.G. Ryan 9

1 University of Chicago, Department of Astronomy and Astrophysics, 5640 S. Ellis Ave, Chicago, IL 60637, USA
(duncan, rebull, primas@oddjob.uchicago.edu)
2 Adler Planetarium, Chicago, IL, USA
3 European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching, Germany
4 University of Hawaii Institute for Astronomy, 2680 Woodlawn Dr, Honolulu, HI 96822, USA (boes@galileo.ifa.hawaii.edu)
5 Beatrice Watson Parrent Postdoctoral Fellow, Hubble Postdoctoral Fellow
6 Yale University, Department of Astronomy, P.O. Box 208101, New Haven, CT 06520-8101, USA (con@athena.astro.yale.edu)
7 University of Chicago, Yerkes Observatory, Williams Bay, WI 53191-0258, USA (hobbs@hale.yerkes.uchicago.edu)
8 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA (jking@stsci.edu)
9 Royal Greenwich Observatory, Madingley Road, Cambridge CB3 0EZ, UK (sgr@ast.cam.ac.uk)

Received 5 August 1997 / Accepted 5 January 1998


The Goddard High Resolution Spectrograph (GHRS) of the Hubble Space Telescope (HST) has been used to observe the boron 2500 Å region of BD -13 3442. At a metallicity of [Fe/H]=-3.00 this is the most metal-poor star ever observed for B. Nearly 26 hours of exposure time resulted in a detection. Spectrum synthesis using the latest Kurucz model atmospheres yields an LTE boron abundance of log [FORMULA] (B) [FORMULA]. This value is consistent with the linear relation of slope [FORMULA] 1.0 between log [FORMULA] ([FORMULA]) and [Fe/H] found for 10 halo and disk stars by Duncan et al. (1997). Using the NLTE correction of Kiselman & Carlsson (1996), the NLTE boron abundance is log [FORMULA] (B) [FORMULA]. This is also consistent with the NLTE relation determined by Duncan et al. (1997) where the slope of log [FORMULA] ([FORMULA]) vs. [Fe/H] is [FORMULA] 0.7.

These data support a model in which most production of B and Be comes from the spallation of energetic C and O nuclei onto protons and He nuclei, probably in the vicinity of massive supernovae in star-forming regions, rather than the spallation of cosmic ray protons and alpha particles onto CNO nuclei in the general interstellar medium.

Key words: stars: individual: BD  – 13 3442 – stars: abundances – stars: population II – Galaxy: abundances – Galaxy: evolution

* This research was based on observations obtained with the NASA/ESA Hubble Space Telescope through the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555

Send offprint requests to: D.K. Duncan

© European Southern Observatory (ESO) 1998

Online publication: March 30, 1998