MOST satellite photometry of stars in the M67 field: Eclipsing binaries, blue stragglers and delta-Scuti variables

Abstract

We present two series of MOST (Microvariability & Oscillations of STars) space-based photometry, covering nearly continuously 10 days in 2004 and 30 days in 2007, of selected variable stars in the upper Main Sequence of the old open cluster M67. New high-precision light curves were obtained for the blue-straggler binary/triple systems AH Cnc, ES Cnc and EV Cnc. The precision and phase coverage of ES Cnc and EV Cnc is by far superior to any previous observations. The light curve of ES Cnc is modelled in detail, assuming two dark photospheric spots and Roche geometry. An analysis of the light curve of AH Cnc indicates a low mass ratio (q about 0.13) and a high inclination angle for this system. Two new long-period eclipsing binaries, GSC 814-323 and HD75638 (non-members of M67) were discovered. We also present ground-based DDO spectroscopy of ES Cnc and of the newly found eclipsing binaries. Especially interesting is HD75638, a member of a visual binary, which must itself be a triple or a higher-multiplicity system. New light curves of two delta Scuti pulsators, EX Cnc and EW Cnc, have been analyzed leading to detection of 26 and 8 pulsation frequencies of high temporal stability.

arXiv commentaccepted to MNRAS, 2008 August 28

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Cited by in corpus (15)

• Stellar Radial Velocities in the Old Open Cluster M67 (NGC 2682) I. Memberships, Binaries, and Kinematics
• Variable stars in one open cluster within the Kepler/K2-Campaign-5 field: M 67 (NGC 2682)
• Close binary stars in the solar-age Galactic open cluster M67
• A PSF-based approach to Kepler/K2 data - III. Search for exoplanets and variable stars within the open cluster M 67 (NGC 2682)
• CoBiToM Project -- I. Contact Binaries Towards Merging
• Studying bright variable stars with the Multi-site All-Sky CAmeRA (MASCARA)
• Orbital and physical parameters of eclipsing binaries from the ASAS catalogue -- III. Two new low-mass systems with rapidly evolving spots
• A chemical study of M67 candidate blue stragglers and evolved blue stragglers observed with APOGEE DR14
• Apex determination and detection of stellar clumps in the open cluster M 67
• A study of the blue straggler population of the old open cluster Collinder 261
• The RR Lyrae Delay-Time Distribution: A Novel Perspective on Models of Old Stellar Populations
• DDO spectroscopic survey of MOST variable stars
• The K2 M67 Study: A Curiously Young Star in an Eclipsing Binary in an Old Open Cluster
• The TAOS Project Stellar Variability I. Detection of Low-Amplitude delta Scuti Stars
• Search for transiting exoplanets and variable stars in the open cluster NGC 7243