NOAO >   Observing Info >   Approved Programs >   2011B-0463

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Proposal Information for 2011B-0463


PI: Waqas A. Bhatti, Johns Hopkins University, waqas@pha.jhu.edu
Address: Department of Physics & Astronomy, 3400 N Charles Street, Baltimore, Maryland 21218, USA

CoI: Holland C. Ford, Johns Hopkins University
CoI: Larry D. Petro, Space Telescope Science Institute
CoI: Michael W. Richmond, Rochester Institute of Technology

Title: Eclipse Photometry and Radial Velocity Measurements of Four M-Dwarf Eclipsing Binaries from SDSS Stripe 82

Abstract: Recent observations of low-mass (M < 0.6 M_\odot) eclipsing binaries (EBs) suggest that stellar structure models systematically under-predict the radii of the stars in these objects by ~ 10%. Tidal effects and rotation-induced magnetic fields in close binaries may be responsible for these `inflated' radii. This scenario may be tested by characterizing the relation between orbital period and the ratio of predicted to observed stellar radii. The small number of observed low- mass EBs, however, makes any trend in this relation difficult to quantify. We recently identified 104 M-dwarf EBs from SDSS Stripe 82 time-series photometry. From this sample, we selected four bright targets with periods < 1.5 d for follow-up observations. Here, we propose to use the KPNO 2.1-m telescope to obtain well-sampled light- curves, along with the KPNO 4-m telescope and R-C spectrograph to measure radial velocities, resulting in precise estimates of masses and radii. These observations will help clarify the relation between orbital period and radius discrepancy and characterize the influence of rotation-induced magnetic fields on the radii of low-mass stars in close binaries.


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NOAO >   Observing Info >   Approved Programs >   2011B-0463

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