THE BORON ABUNDANCE OF PROCYON

The B I 2496.8 angstrom resonance line and HST/GHRS echelle spectra ar e used with model atmospheres and synthetic spectra to derive the B ab undance of the F dwarfs Procyon (alpha Canis Minoris), theta Ursae Maj oris, and iota Pegasi. The B abundance [log epsilon (B) congruent-to 2 .3] of theta UMa and iota Peg is similar to that derived by Boesgaard and Heacox from the B II resonance line in spectra of A- and B-type st ars. These two dwarfs show normal abundances of Li, Be, and B. Procyon , which is highly depleted in Li and Be, is depleted in B by a factor of at least 3. Comparison of the spectra of Procyon and the halo dwarf HD 140283 shows that the B abundance assigned by Duncan et al. (1992, ApJ, 401, 584) to three halo dwarfs is not greatly overestimated as a result of contamination of the B I line by an unidentified line.