NOAO >   Observing Info >   Approved Programs >   2012A-0049

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Proposal Information for 2012A-0049


PI: Steve B. Howell, NASA Ames Research Center, howell@noao.edu
Address: Astrophysics, P.O. Box 1 M/S 244-30, Moffett Field, CA 94035, US

CoI: Mark Everett, NOAO
CoI: Elliott Horch, Southern Connecticut State University
CoI: David Ciardi, CalTech/NexSci

Title: Speckle and Lucky Imaging of Kepler Exoplanet Candidate Host Stars

Abstract: Kepler monitors 150,000+ stars and detects candidate transiting planets by their light curve signatures. These transits are distinguishable from those of eclipsing binary stars chiefly by virtue of a sufficiently small transit depth given the spectral class assumed for the host star. In order to measure planet sizes, and to distinguish true planets from eclipsing binaries, it is necessary to account for all stars whose profiles blend together and contribute flux to Kepler's photometry. Some blends can be detected and false positives eliminated based on Kepler data alone, but in many cases high resolution ground- based imaging is needed to accurately map out the brightness and location of multiple stars to model their effects on the light curves. While Earth-sized exoplanets, esp. those in long period orbits, are hard to confirm from the ground and for most, radial velocities will not be forthcoming, false positive elimination relies on ground-based imaging coupled with the Kepler data itself and model techniques. Follow-up for Kepler exoplanet candidates is now focused on Super-earth and earth-size planets and the highest priority need for ground-based follow-up is high resolution optical imaging. This proposal aims to obtain high resolution imaging of Kepler exoplanet transit candidates in order to find any spatially close companion stars and eliminate the largest false positive contributor - (background) eclipsing binary stars or variable faint companion stars. Additionally, third-light dilution to a true planet transit can lead to an underestimate of the exoplanet radii and masses by 10-15% and 60% or more respectively.


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