AAS 203rd Meeting, January 2004
Session 85 Stellar Structure, Evolution and Abundances
Poster, Wednesday, January 7, 2004, 9:20am-6:30pm, Grand Hall

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[85.07] Spectral Indices of Old Stars as a Function of Alpha Element Abundance Ratios

M. Houdashelt (Johns Hopkins Univ.)

As part of a program to produce fully self-consistent evolutionary synthesis models, we are calculating a large grid of synthetic stellar spectra for low-mass stars with metallicities spanning the range from old, Milky Way globular clusters to massive, early-type galaxies. This grid includes models having both solar abundance ratios and enhanced [alpha/Fe] ratios. From these spectra, we measure the Lick indices, as well as the strengths of the Ca II triplet, the near-infrared CO bands, and a variety of atomic and molecular lines in the H and K bandpasses. In this poster, we show examples of spectral features that vary as functions of temperature, gravity, metallicity, and [alpha/Fe] ratio and discuss their utility in interpreting integrated-light models and observations.

This work is funded by NASA Grant NAG5-10922.

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