The Abundance of Boron in Disk-Metallicity Stars

Although the behavior of boron versus metallicity has been probed in a fairly large sample of halo dwarfs with HST, it is only very recently that boron abundances have been derived systematically in solar metallicity dwarfs. This effort began with a re-analysis of the solar spectrum with modern atomic data and model atmospheres so that the Sun could be adopted as a standard for the calibration of a line list in the region of the B I transition at 2497 Â. The solar analysis indicates that boron is not depleted in the solar photosphere. From a subsequent study of a sample of 14 field F/G-dwarfs with roughly solar metallicities, it is found that the behavior of boron versus [Fe/H] follows the linear trend that is observed for the halo stars. The average B/Be obtained for solar metallicity stars is 27±5 compared to the solar ratio of 23. The determination of boron abundances in the young B-type and G-type stars of the Orion association reveals a behavior of boron and oxygen in Orion that is opposite of the positive correlation which is observed for the field stars: the boron and oxygen abundances are anticorrelated.