  We propose to use Kepler in 2-wheel mode to conduct a detailed search for
Earth-sized planets orbiting ultra-cool stars and brown dwarfs (spectral types
from M7 to L3). This population of objects presents several advantages for
exoplanet surveys. First, ultra-cool stars and brown dwarfs are small and thus
result in favorable planet-to-star area ratios. Second, because of their low
effective temperature, the inner edge of their habitable zone is extremely
close (2 to 3 days only). Third, our targets are bright at infrared
wavelengths, which will enable detailed follow-up studies. Our program
therefore represents a unique opportunity to find a transiting Earth-size
exoplanet for which atmospheric features (including biosignatures) could be
detected with near-to-come facilities such as JWST. Such exoplanet has not been
discovered yet. Kepler in 2-wheel mode provides the required stability and
photometric precision to make this survey successful. Our initial target sample
includes 60 ultra-cool stars and brown dwarfs from which we expect to detect at
least one transiting planet. We propose to monitor each source for 4 days,
resulting in a total program duration of ~240 days.
