AAS 199th meeting, Washington, DC, January 2002
Session 54. Galaxies - Various
Display, Tuesday, January 8, 2002, 9:20am-6:30pm, Exhibit Hall

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[54.05] Boron in the Small Magellanic Cloud: A Novel Test of Light Element Formation

A.M. Brooks (Columbia University), K.A. Venn (Macalester College), D.L. Lambert (Univ. Texas, Austin), M. Lemke (Sternwarte, Bamberg), K. Cunha (Observatorio Nacional, Brazil), V.V. Smith (Univ. Texas, El Paso)

Hubble Space Telescope STIS observations of the \ion{B}{3} resonance line at 2066~Å\ have been obtained and analyzed for two Small Magellanic Cloud (SMC) B-type stars. Boron is not detected in either star. However, upper limits to the boron abundance are set, with 12+log(B/H) \le 1.6 for both AV\,304 and NGC\,346-637. These results suggest that boron may scale quadratically with oxygen (B \alpha O2) in the SMC, as is expected for a pure cosmic-ray spallation standard model. However, the results are also consistent with the scaling law B \alpha O1.4 found for F and G dwarfs in the disk of the Galaxy by Smith etal (2001). Also, mixing due to rapid-rotation could have depleted boron in our SMC B-star targets.

The UV spectrum of AV\,304 has also been used to determine an iron-group abundance, [Fe/H]=-0.6±0.2, from both an absolute and a differential analysis, with respect to the Galactic B-star HD\,36591. This is consistent with results from the A-F supergiants in the SMC.

Support for proposal GO#08161 was provided by NASA through a grant from the Space Telescope Science Institute.

The author(s) of this abstract have provided an email address for comments about the abstract: abrooks@astro.columbia.edu

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