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Detection of Beat Cepheids in M33 and Their Use as a Probe of the M33 Metallicity Distribution

J. -P. Beaulieu·J. Robert Buchler·J. -B. Marquette·J. D. Hartman·A. Schwarzenberg-Czerny
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Abstract

Our analysis of the Deep CFHT M33 variability survey database has uncovered 5 Beat Cepheids (BCs) that are pulsating in the fundamental and first overtone modes. With {\it only} the help of stellar pulsation theory and of mass--luminosity (M-L) relations, derived from evolutionary tracks, we can accurately determine the metallicities Z of these stars. The [O/H] metallicity gradient of -0.16 dex/kpc that is inferred from the M33 galacto-centric distances of these Cepheids and from their 'pulsation' metallicities is in excellent agreement with the standard spectroscopic metallicity gradients that are determined from H II regions, early B supergiant stars and planetary nebulae. Beat Cepheids can thus provide an additional, independent probe of galactic metallicity distributions.

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J. -P. Beaulieu, J. Robert Buchler, J. -B. Marquette, J. D. Hartman, A. Schwarzenberg-Czerny. 2006-10-25. Detection of Beat Cepheids in M33 and Their Use as a Probe of the M33 Metallicity Distribution. https://doi.org/10.1086/510453

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