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The MACHO Project Large Magellanic Cloud Variable Star Inventory. VIII. The Recent Star Formation History of the LMC from the Cepheid Period Distribution

Alcock, C and Allsman, RA and Alves, DR and Axelrod, TS and Becker, AC and Bennett, DP and Bersier, DF and Cook, KH and Freeman, KC and Griest, K and Guern, JA and Lehner, M and Marshall, SL and Minniti, D and Peterson, BA and Pratt, MR and Quinn, PJ and Rodgers, AW and Stubbs, CW and Sutherland, W and Tomaney, A and Vandehei, T and Welch, DL (1999) The MACHO Project Large Magellanic Cloud Variable Star Inventory. VIII. The Recent Star Formation History of the LMC from the Cepheid Period Distribution. The Astrophysical Journal, 117 (2). pp. 920-926. ISSN 1538-4357

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Abstract

We present an analysis of the period distribution of $\sim 1800$ Cepheids in the Large Magellanic Cloud, based on data obtained by the MACHO microlensing experiment and on a previous catalogue by Payne-Gaposchkin. Using stellar evolution and pulsation models, we construct theoretical period-frequency distributions that are compared to the observations. These models reveal that a significant burst of star formation has occurred recently in the LMC ($\sim 1.15\times 10^8$ years). We also show that during the last $\sim 10^8$ years, the main center of star formation has been propagating from SE to NW along the bar. We find that the evolutionary masses of Cepheids are still smaller than pulsation masses by $\sim 7$ % and that the red edge of the Cepheid instability strip could be slightly bluer than indicated by theory. There are $\sim 600$ Cepheids with periods below $\sim 2.5$ days cannot be explained by evolution theory. We suggest that they are anomalous Cepheids; a number of these stars are double-mode Cepheids.

Item Type: Article
Uncontrolled Keywords: astro-ph; astro-ph
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: American Astronomical Society
Related URLs:
Date Deposited: 18 Oct 2016 10:38
Last Modified: 18 Oct 2016 10:38
DOI or Identification number: 10.1086/300736
URI: http://researchonline.ljmu.ac.uk/id/eprint/4635

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