2005/10/19 by Janusz Kaluzny, Stefan Mochnacki, Slavek M. Rucinski
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/497967
published as Astron.J.131:407-413,2006 · 17 pages, incl. 8 figures, 2 tables + additional data table. Accepted for publication in The Astronomical Journal, Jan. 2006
arxiv created 2005/10/19 · openalex publication_date 2006/01/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We observed a field in the disk of the LMC on two consecutive nights in search of rapid variable stars. We found two pulsating stars of type RRab and δ Scuti and four binary stars; among the latter we found one sdB or cataclysmic variable below the LMC blue main sequence and three very close binary systems on the main sequence. At least one of the main-sequence binaries, and possibly all three, are the first solar-type (W UMa–type) contact binaries to be detected in any extragalactic system and observed to obey the same M V = M V (log P , B - V ) calibration as the Galactic systems. Given the selection effects due to small amplitudes at faint magnitudes, the frequency of such binaries in the disk of the LMC with its large spread in population ages is not inconsistent with that in the disk of our Galaxy and contrasts with the lack of binaries found in earlier observations of the much younger LMC cluster LW 55.