AAS 203rd Meeting, January 2004
Session 6 Brown Dwarf Stars
Poster, Monday, January 5, 2004, 9:20am-6:30pm, Grand Hall

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[6.07] Fossils in the Photosphere: Condensation Temperature Trends in the Chemical Abundances of Stars with Radial-Velocity Companions

C. Laws (University of Washington), G. Gonzalez (Iowa State University), K. M. Walker (Ohio State University), S. Tyagi, J. Dodsworth, K. Snider (University of Washington), N. B. Suntzeff (Cerro Tololo Inter-American Observatory)

We present [X/Fe] values, derived from high-resolution spectroscopic analyses, for 18 elements observed in 65 stars with giant planet and/or brown dwarf companions. The wide range of condensation temperatures of the elements studied permits a reliable estimation of the correlation between condensation temperature and chemical abundance for each star. We employ these results, along with recently improved estimates of the masses of the stars themselves, to thoroughly investigate the possibility that the photospheres of these stars have been systematically polluted by material depleted in volatile elements. Additionally, we perform similar but more precise differential analyses on two star systems in which only one member is observed to possess a planetary companion 16 Cygni A & B, and HD219542 A & B. We compare the differential abundance patterns between the primary and secondary in each case, and investigate the hypothesis that the observed chemical variations in these specific instances might be attributed to differential accretion of circumstellar material. We gratefully acknowledge the support of this work by the University of Washington Astrobiology Program and a grant from the National Astrobiology Institute.

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

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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.