Population I pulsating stars

Tsvetkov, Ts.

doi:10.1007/bf00643628

Cited by 3 publications

(1 citation statement)

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“…Therefore, by taking into account the Mass-Luminosity relation and the stellar ages predicted by evolutionary models, it was soon recognized (Kippenhahn & Smith 1969;Meyer-Hofmeister 1969) that an increase in the pulsation period implies an increase in the stellar mass, and in turn a decrease in the Cepheid age. On the basis of these plane physical arguments Efremov (1978) derived an empirical PA relation by adopting Cepheids in Galactic, in M31, and in Large Magellanic Cloud (LMC) clusters, whose age was independently estimated (see also Tsvetkov 1989). More recently, Magnier et al (1997, hereinafter M97) derived a new semi-empirical PA relation and used Cepheids in NGC206, the super-association in M31, to trace the age distribution, and in turn the star formation history in this region, located at the intersection of two spiral arms.…”

Section: Introductionmentioning

confidence: 99%

Classical Cepheid Pulsation Models. X. The Period‐Age Relation

Bono

Marconi

Cassisi

et al. 2005

ApJ

158

237

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We present new Period-Age (PA) and Period-Age-Color (PAC) relations for fundamental and first overtone classical Cepheids. Current predictions rely on homogeneous sets of evolutionary and pulsation models covering a broad range of stellar masses and chemical compositions. We found that PA and PAC relations present a mild dependence upon metal content. Moreover, the use of different PA and PAC relation for fundamental and first overtone Cepheids improves the accuracy of age estimates in the short-period (log P < 1) range (old Cepheids), because they present smaller intrinsic dispersions. At the same time, the use of the PAC relations improves the accuracy in the long-period (log P ≥ 1) range (young Cepheids), since they account for the position of individual objects inside the instability strip.We performed a detailed comparison between evolutionary and pulsation ages for a sizable sample of LMC (15) and SMC (12) clusters which host at least two Cepheids. In order to avoid deceptive uncertainties in the photometric absolute zero-point, we adopted the homogeneous set of B,V,I data for clusters and Cepheids collected by OGLE. We also adopted the same reddening scale. The different age estimates agree at the level of 20% for LMC clusters and of 10% for SMC clusters. We also performed the same comparison for two Galactic clusters (NGC6067, NGC7790) and the difference in age is smaller than 20%.These findings support the use of PA and PAC relations to supply accurate estimates of individual stellar ages in the Galaxy and in external Galaxies. The main advantage of this approach is its independence from the distance.

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Section: Introductionmentioning

confidence: 99%