The Unique Properties of omega Centauri Seen Through Stroemgren Eyes
Abstract
A revised metallicity calibration of the Stroemgren (b-y),m_1 diagram, based on a sample of globular cluster and field red giant stars, is presented. This new calibration has been used to determine Stroemgren metallicities ([Fe/H]_phot) for more than 1400 red giants in omega Centauri. Most of the stars belong to a metal poor ([Fe/H]_phot = -1.7 dex), old population. A second more metal rich ([Fe/H]_phot = -0.9 dex) population is found to be about 3 Gyr younger and more centrally concentrated than the old one. The CN-rich stars do not seem to follow the radial distribution of the metal rich population.
Keywords
Cite
@article{arxiv.astro-ph/9910370,
title = {The Unique Properties of omega Centauri Seen Through Stroemgren Eyes},
author = {M. Hilker and T. Richtler},
journal= {arXiv preprint arXiv:astro-ph/9910370},
year = {2007}
}
Comments
6 pages, 6 figures, in Proceedings of the 35th Liege International Astrophysics Colloquium: "The Galactic Halo: from Globular Clusters to Field Stars", July 5-8, 1999