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Paper: Dwarf Cepheids in the Carina dwarf galaxy
Volume: 10, Evolution of the Universe of Galaxies: Edwin Hubble Centennial Symposium
Page: 134
Authors: Nemec, James; Mateo, Mario
Abstract: The discovery of about 15 dwarf Cepheids in a 4 x 4-arcmin field in the Carina dwarf galaxy is reported. Light curves are presented for the nine stars that have known periods. The periods range from 0.051 to 0.072 d, the visual amplitudes are between 0.10 to 0.60 mag, and the mean visual magnitudes are in the interval 21.3 to 23.2 mag. If the nine variables are 15 Gyr old and are similar to the SX Phe stars found recently in several globular clusters, then seven of the stars appear to obey the fundamental-mode P-L relationship. Two of the stars are unusually luminous and may be long-period first-overtone pulsators. On the other hand, since 70 percent or more of the stars in Carina are about 7 Gyr old, with Fe/H approximately equal to -1.9, it is also possible that some of the stars are of intermediate age. In a deep c-m diagram all of the variables appear to be luminous main-sequence stars. The fact that there is only a small number of faint subgiants at the base of the red giant branch supports the Mould and Aaronson conclusion that the fraction of 15-Gyr-old stars in Carina is very low.
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