NOAO >   Observing Info >   Approved Programs >   2010B-0434

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Proposal Information for 2010B-0434


PI: Andrej Pr\v sa, Villanova University, andrej.prsa@villanova.edu
Address: Astronomy Department, 800 E Lancaster Ave, Villanova, PA 19085, USA

CoI: Edward Guinan, Villanova University
CoI: Frank Maloney, Villanova University
CoI: Scott Engle, Villanova University
CoI: Brian Kirk, Villanova University
CoI: Cindy Villamil, Villanova University

Title: Follow-up Spectroscopy of Prime W-UMa Type Binary Stars Observed by Kepler

Abstract: Overcontact binary stars (W UMa-type binaries) are one of most ubiquitous close binaries in our Galaxy. The components evolved into a system that shares a common envelope and features active mass transfer. Because of the components' proximity, orbital periods of these systems are short (2-18 hours) and the orbital velocities are large (100- 300 km/s). It might be expected that overcontact binary envelopes are in thermal contact, yet the observations indicate otherwise. In April 2010 we were successful in proposing for ultra-high precision ( 60ppm) photometry of 50 select W UMa-type binaries through the Kepler mission's Cycle II Guest Observer program. Through this NOAO proposal we plan to acquire high-resolution echelle spectra of 20 brightest program stars and use them to determine the systems' radial velocities near quadrature phases. These will provide us with the masses, projected semi-major axes, and center-of-mass radial velocities of program stars, and allow us, in conjunction with the Kepler data, to \emphcompletely characterize the absolute properties (masses, radii, temperatures, luminosities) of these prime W UMa-type binaries.


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NOAO >   Observing Info >   Approved Programs >   2010B-0434

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