PI: Mark E. Everett, NOAO, email@example.com
Address: SCI, 950 N. Cherry Ave., Tucson, AZ 85719, USA
CoI: Steve B. Howell, NASA ARC
CoI: David R. Silva, NOAO
CoI: Paula Szkody, University of Washington
Title: Spectroscopy of Kepler Candidate Exoplanet Host Stars
Abstract: Currently the NASA \it Kepler Mission has identified 3449 exoplanet candidates, one third with estimated radii \rm R_p<2.5R_\oplus and orbiting faint (\rm m_Kep>14.5) host stars. The NASA sponsored \it Kepler Follow-up Program is focusing on small exoplanet candidates (\rm R_p<2.5R_\oplus) and those in habitable zone orbits. Planet radii estimates depend on estimates of host star radii. Based on spectra previously obtained at the KPNO Mayall 4-m for 220 stars with candidate exoplanets, Everett et al. (2013) have shown that many host stars are larger than originally assumed (up to factor of 2). Therefore, the exoplanet candidates they host must be larger than originally assumed, which conversely reduces the number of known Earth- sized exoplanet candidates. Determination of the frequency of such Earth-sized planets is a cornerstone \it Kepler mission objective and of keen general interest. These Mayall spectra were also used to confirm the Buchhave et al. (2012) result that exoplanet candidates larger than \rm 4R_\oplus in short-period orbits are preferentially associated with host stars with solar or higher metallicity, using a fainter and larger sample of stars than Buchhave et al. In short, followup Mayall optical spectroscopy is \bf critical to confirming the detection of Earth-sized exoplanets, a \it Kepler cornerstone goal, as well as characterizing the relationship between host star properties and planetary system properties. Here, we propose to continue our reconnaissance survey with a focus on the smallest (most rare) exoplanet candidates orbiting the faintest \it Kepler host stars.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360