AAS 200th meeting, Albuquerque, NM, June 2002
Session 7. Variable Stars and Relatives
Display, Monday, June 3, 2002, 9:20am-6:30pm, SW Exhibit Hall

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[7.14] Boron in Solar-Type Galactic Disk Stars

E. J. McGrath, A. M. Boesgaard (IfA, Univ. of Hawaii), D. L. Lambert (UT-Austin), K. Cunha (ON/MCT, Brazil)

This is the first study of the abundance of boron in Population I solar-type stars that are undepleted in beryllium. The requirement that the stars be undepleted in Be ensures that they have also retained their full initial abundance of boron, and thus provides a means to study the evolution of B in the Galactic disk. Using the STIS echelle spectrograph onboard HST, we observed sixteen bright stars around the B I 2497 Å line. Ten of these stars had corresponding Keck HIRES data which was used to determine spectroscopic temperatures and new metallicity values. Previous abundance studies of Li and Be in these stars were reevaluated using these revised parameters for consistency. Boron abundances were calculated by fitting the data to a modified spectral synthesis code which accounts for the increased opacity in the UV due to metals, and were then corrected for non-LTE effects.

We find that the trend of boron abundance with metallicity is consistent with the general trend observed in halo stars, although there may be a slight flattening of the slope in the disk. In addition, the abundance of B is observed to be a factor of ~15 more than the abundance of Be in these stars.

This work was funded by HST grant GO-087701.

The author(s) of this abstract have provided an email address for comments about the abstract: mcgrath@ifa.hawaii.edu

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Bulletin of the American Astronomical Society, 34
© 2002. The American Astronomical Soceity.