NOAO >   Observing Info >   Approved Programs >   2012A-0528

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Proposal Information for 2012A-0528


PI: Jon Mauerhan, UA Steward Observatory, mauerhan@ipac.caltech.edu
Address: 933 North Cherry Ave, Rm. N204, Tucson, AZ 85721, USA

Title: A Search for Eclipses from Three Extraordinary Massive Colliding-Wind Binaries

Abstract: The most massive stars known are the hydrogen-rich Wolf-Rayet stars (WNH), as evidenced by direct dynamical mass measurements of these stars in close eclipsing binaries. Such systems have important implications for the uncertain upper stellar mass limit and for the formation mode for the most massive stars. We have recently discovered three new WNH counterparts to luminous hard X-ray sources in the Galactic plane, whose X-ray and radio properties suggest that they are close binaries in which the high-energy emission is the result of colliding stellar winds. The large physical radii of WNH stars suggest there is a sufficiently high likelihood that eclipses will be observable in these binaries over timescales of several days to weeks, which warrants a photometric monitoring campaign. We thus propose to photometrically monitor our three newly discovered WNH colling-wind binary systems in 2012A to search for evidence of eclipses. Successful detection of eclipses or some other rotationally modulated signal will solidify the binary hypothesis for these new discoveries and, moreover, will constrain their separations and mass functions.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2012A-0528

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