Kepler Planet Occurrence Rates for Mid-Type M Dwarfs

Kevin Hardegree-Ullman (Toledo/IPAC)
July 14, 2017 - 12:15pm


Planet occurrence rates increase toward later spectral types; therefore, M dwarf systems are our most promising targets in the search for exoplanets. The identification and characterization of stars in the original Kepler field was accomplished using photometry alone, resulting in large uncertainties for late-type stars like M dwarfs. In order to more accurately compute the planet occurrence rate around mid-type M dwarfs, we need to better constrain stellar radii, which strongly correlate with temperature and metallicity. These measurements need to be performed on a statistically significant population of stars including systems with and without planets. Therefore, we have begun to characterize the properties of the 559 probable mid-type M dwarfs in the Kepler field using optical spectra from WIYN and the Discovery Channel Telescope and infrared spectra from IRTF in order to constrain the planet occurrence rate for such stars. I will be presenting results from our spectroscopic observations, including new stellar parameters and preliminary planet occurrence rates for mid-type M dwarfs.