The macho project LMC variable star inventory. VIII. The recent star formation history of the large magellanic cloud from the cepheid period distribution

C. Alcock, R. A. Allsman, D. R. Alves, T. S. Axelrod, A. C. Becker, D. P. Bennett, D. F. Bersier, K. H. Cook, K. C. Freeman, K. Griest, J. A. Guern, M. Lehner, S. L. Marshall, D. Minniti, B. A. Peterson, M. R. Pratt, P. J. Quinn, A. W. Rodgers, C. W. Stubbs, W. SutherlandA. Tomaney, T. Vandehei, D. L. Welch

Research output: Contribution to journalArticlepeer-review

40 Citations (Scopus)

Abstract

We present an analysis of the period distribution of about 1800 Cepheids in the LMC, based on data obtained by the MACHO microlensing experiment and on a previous catalog by C. H. Payne Gaposchkin. Using stellar evolution and pulsation models, we construct theoretical period-frequency distributions that are compared with the observations. These models reveal that a significant burst of star formation has occurred recently in the LMC (∼1.15 × 108 yr). We also show that during the last ∼ 108 yr, the main center of star formation has been propagating from southeast to northwest along the bar. We find that the evolutionary masses of Cepheids are still smaller than pulsation masses by ∼7% and that the red edge of the Cepheid instability strip could be slightly bluer than indicated by theory. There are approximately 600 Cepheids with periods below ∼2.5 days that cannot be explained by evolution theory. We suggest that they are anomalous Cepheids and that a number of these stars are double-mode Cepheids.

Original languageEnglish
Pages (from-to)920-926
Number of pages7
JournalAstronomical Journal
Volume117
Issue number2
DOIs
Publication statusPublished - Feb 1999

Keywords

  • Cepheids
  • Magellanic clouds
  • Stars: formation

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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