Katia Cunha (1, 4), Kris Sellgren (2), Verne V. Smith (1), Solange V. Ramirez (3), Robert D. Blum (1, 5), and Donald M. Terndrup (2)
ApJ, in press, November 10 issue, 2007 (arXiv:0707.2610)
We present chemical abundances in a sample of luminous cool stars located within 30 pc of the Galactic Center. Abundances of carbon, nitrogen, oxygen, calcium, and iron were derived from high-resolution infrared spectra in the H- and K-bands. The abundance results indicate that both [O/Fe] and [Ca/Fe] are enhanced respectively by averages of +0.2 and +0.3 dex, relative to either the Sun or the Milky Way disk at near solar Fe abundances. The Galactic Center stars show a nearly uniform and nearly solar iron abundance. The mean value of A(Fe) = 7.59 +- 0.06 agrees well with previous work. The total range in Fe abundance among Galactic Center stars, 0.16 dex, is significantly narrower than the iron abundance distributions found in the literature for the older bulge population. Our snapshot of the current-day Fe abundance within 30 pc of the Galactic Center samples stars with an age less than 1 Gyr; a larger sample in time (or space) may find a wider spread in abundances.
(1) National Optical Astronomy Observatory
(2) Ohio State University
(3) Infrared Processing and Analysis Center, Caltech
(4) on leave from Observatorio Nacional, Rio de Janeiro, Brazil
(5) Based on observations obtained at the Gemini Observatory,
which is operated by the Association
of Universities for Research in Astronomy, Inc., under a cooperative
agreement with the NSF on behalf of the Gemini partnership.
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Revised: 2007 October 5 (ks)