Photospheric Metals in the [ITAL]Far Ultraviolet Spectroscopic Explorer[/ITAL] Spectrum of the Subdwarf B Star PG 0749+658

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Abstract
We present an abundance analysis of the far-ultraviolet (905-1187 Å) spectrum of the subdwarf B star PG 0749+658 obtained by the Far Ultraviolet Spectroscopic Explorer. The data have a resolution of about R = λ/Δλ = 12000-15000 Å (20-25 km s-1). We determine C, N, Si, P, S, Cr, Mn, Fe, Co, and Ni abundances, and upper limits on the abundance of Cl and V, using a grid of synthetic spectra based on an LTE stellar atmosphere model. He, C, N, Si, and Cl are depleted by a factor of 10 with respect to the solar abundance, while P, S, and Fe are diminished by less than a factor of 10. We measure a solar abundance of Cr, Mn, and Co and a Ni enhancement of ~0.6 dex. We compare these values with predictions based on radiative levitation theory.