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

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

Research output: Contribution to journalArticlepeer-review

53 Scopus citations

Abstract

Boron abundances have been derived for seven main-sequence B-type stars from Hubble Space Telescope STIS spectra around the B III λ2066 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 ni 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 (US)
Pages (from-to)571-586
Number of pages16
JournalAstrophysical Journal
Volume565
Issue number1 I
DOIs
StatePublished - Jan 20 2002
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Stars: abundances
  • Stars: evolution
  • Stars: rotation

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