BORON IN THE VERY METAL-POOR STAR BD-13-3442

The Goddard High Resolution Spectrograph (GHRS) of the Hubble Space Te lescope (HST) has been used to observe the boron 2500 Angstrom 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 resul ted in a detection. Spectrum synthesis using the latest Kurucz model a tmospheres yields an LTE boron abundance of log epsilon(B)=+0.01+/-0.2 0. This value is consistent with the linear relation of slope similar to 1.0 between log epsilon(BLTE) 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 epsilon(B)=+0.93+/- 0.20. This is also consistent with the NLTE relation determined by Dun can et al. (1997) where the slope of log epsilon(B-LTE) VS [Fe/H] is s imilar to 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 pr otons and He nuclei, probably in the vicinity of massive supernovae in star-forming regions, rather than the spallation of cosmic ray proton s and alpha particles onto CNO nuclei in the general interstellar medi um.