Kepler-37 is a Sun-like G-type star (about 0.79 solar masses, 5,357 K, 0.79 solar radii), 63.9 light-years from Earth. Kepler-37 b was announced as a planet smaller than Mercury, one of the smallest worlds found by Kepler. Kepler-37 b is a 0.8-Earth-mass planet, with an orbital period of 13.4 days, at 0.102 AU from its star, and an equilibrium temperature near 718 K, on an eccentric orbit (e ≈ 0.10), discovered in 2013 via transit. Kepler-37 c is a 1.3-Earth-mass planet, with an orbital period of 21.3 days, at 0.139 AU from its star, and an equilibrium temperature near 615 K, on an eccentric orbit (e ≈ 0.10), discovered in 2013 via transit.