Boron abundances in B-type stars: A test of rotational depletion during main-sequence evolution

Francis Keenan, K.A. Venn, A.M. Brooks, D.L. Lambert, M. Lemke, N. Langer, D.J. Lennon

Research output: Contribution to journalArticlepeer-review

43 Citations (Scopus)

Abstract

Boron abundances have been derived for seven main-sequence B- type stars from Hubble Space Telescope STIS spectra around the B III lambda2066 line. In two stars, boron appears to be undepleted with respect to the presumed initial abundance. In one star, boron is detectable but is clearly depleted. In the other four stars, boron is undetectable, implying depletions of 1-2 dex. Three of these four stars are nitrogen enriched, but the fourth shows no enrichment of nitrogen. Only rotationally induced mixing predicts that boron depletions are unaccompanied by nitrogen enrichments. The inferred rate of boron depletion from our observations is in good agreement with these predictions. Other boron-depleted nitrogen-normal stars are identified from the literature. In addition, several boron- depleted nitrogen-rich stars are identified, and while all fall on the boron-nitrogen trend predicted by rotationally induced mixing, a majority have nitrogen enrichments that are not uniquely explained by rotation. The spectra have also been used to determine iron group (Cr, Mn, Fe, and Ni) abundances. The seven B-type stars have near-solar iron group abundances, as expected for young stars in the solar neighborhood. We have also analyzed the halo B-type star PG 0832 + 676. We find [Fe/H] = -0.88 +/- 0.10, and the absence of the B III line gives the upper limit [B/H] <-2.5. These and other published abundances are used to infer the star's evolutionary status as a post-asymptotic giant branch star.
Original languageEnglish
Pages (from-to)571-586
Number of pages16
JournalAstrophysical Journal
Volume565
Issue number1 I
Publication statusPublished - 20 Jan 2002

ASJC Scopus subject areas

  • Space and Planetary Science

Fingerprint Dive into the research topics of 'Boron abundances in B-type stars: A test of rotational depletion during main-sequence evolution'. Together they form a unique fingerprint.

Cite this