AAS 199th meeting, Washington, DC, January 2002
Session 137. Topics in Stellar Evolution
Display, Thursday, January 10, 2002, 9:20am-4:00pm, Exhibit Hall

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[137.03] Boron Abundances in Main Sequence B-type Stars: A Test of Rotational Depletion during Main Sequence Evolution

K.A. Venn (U.Minnesota, Macalester College), A.M. Brooks (Columbia U., Macalester College), D.L. Lambert (U.Texas-Austin), M. Lemke (U.Sternwarte-Bamberg), N. Langer (Utrecht), D.J. Lennon (INT, La Palma), F.P. Keenan (Queen's U.-Belfast)

Boron abundances have been derived for seven main sequence B-type stars from HST STIS spectra around the BIII 2066 A line. Boron abundances range from normal to severly depleted. One boron depleted star shows no nitrogen enrichment, which is an abundance pattern uniquely predicted from the rotationally-induced mixing models, e.g., Heger and Langer 2000. Other stars show boron depletions that correlate with nitrogen enrichments; this pattern is predicted by rotationally-induced mixing, but also by other theories. The inferred rate of boron depletion (i.e., boron versus age) from our observations is also in good agreement with the predictions.

Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with proposal GO-7400.

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