They might be giants: luminosity class, planet frequency, and planet-metallicity relation of the coolest Kepler target stars

Andrew W. Mann, Eric Gaidos, Sébastien Lépine +1

We estimate the stellar parameters of late K and early M type Kepler target stars. We obtain medium resolution visible spectra of 382 stars with Kp-J>2 (~K5 and later spectral type…