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Astronomy Reports

, Volume 47, Issue 12, pp 1000–1012 | Cite as

Cepheids in LMC clusters and the period-age relation

  • Yu. N. Efremov
Article

Abstract

We have made a new comparison of the positions of Cepheids and clusters in the LMC and constructed a new empirical period-age relation taking into account all available data on Cepheids in the LMC bar provided by the OGLE project. The most probable relation is logT=8.50−0.65 logP, in reasonably good agreement with theoretical expectations. Numerous Cepheids in rich clusters of the LMC provide the best data for comparing theories of stellar evolution and pulsation and the dynamical evolution of clusters with observations. These data suggest that stars undergoing their first crossing of the instability strip are first-overtone pulsators, though the converse is true of only a small fraction of first-overtone stars. Several rich clusters with suitable ages have no Cepheids—a fact that is not understood and requires verification. Differences in the concentration of Cepheids toward their cluster centers probably reflect the fact that the clusters are at different stages of their dynamical evolution, with the Cepheids in cluster coronas being ejected from the cluster cores during dynamical interactions between stars.

Keywords

Cluster Center Dynamical Evolution Dynamical Interaction Good Data Probable Relation 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© MAIK "Nauka/Interperiodica" 2003

Authors and Affiliations

  • Yu. N. Efremov
    • 1
  1. 1.Sternberg Astronomical InstituteMoscowRussia

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