NOAO >   Observing Info >   Approved Programs >   2013A-0079

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Proposal Information for 2013A-0079


PI: Steve B. Howell, NASA ARC, steve.b.howell@nasa.gov
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: High-resolution Speckle Imaging of Kepler Exoplanet Host Stars - The Search for Other Earths

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 fully determine accurate planet radii, and to distinguish true planets from eclipsing binaries or other false positives, 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 most cases high resolution ground-based imaging is required 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 perfectly validate and for most, radial velocities will not be forthcoming, false positive elimination relies on ground-based hi-resolution imaging coupled with the Kepler data itself and model techniques. Follow-up for Kepler exoplanet candidates in the extended mission is focused on <2.5R_\rm Earth planets and the highest priority need for ground-based follow-up leading to validation 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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