AAS 195th Meeting, January 2000
Session 50. Stellar Atmospheres
Display, Thursday, January 13, 2000, 9:20am-6:30pm, Grand Hall

## [50.08] Boron Abundances in Early-B Stars: The \ion{B}{3} 2065.8 Å\ Line in IUE Data.

C.R. Proffitt (CUA/IACS and STScI/CSC), M.F. Quigley (U. Wisc.)

We have used archival {\em International Ultraviolet Explorer (IUE)}\/ high-dispersion SWP spectra to study the \ion{B}{3} resonance line at 2065.8 Å\ in 44 early-B stars. We find a median boron abundance about half that of solar system meteoritic material, consistent with the values found from high S/N GHRS echelle observations of two of the stars in our sample (Proffitt et al.\ 1999). However, about one third of the stars studied have boron abundances that are a factor of four or more lower than this median, suggesting that envelope mixing deep enough to destroy boron is common. We compare our results to previous determinations of boron abundances in Pop.\ I stars and discuss the implications of our data for non-LTE calculations of boron line formation, the modeling of stellar boron destruction, theories of boron synthesis, and the limits on any intrinsic dispersion in the initial boron abundances of Pop.\ I stars.

This research was supported by NASA grants NAG 5-3487 and HST GO-6644.01-95A.