 Other achievements include discovering the first multiple planet system around a star similar to our own (Upsilon Andromedae), the first transiting planet around another star, simultaneously with David Charbonneau and Timothy Brown (HD209458b), the first extrasolar planet orbiting beyond 5 AU (55 Cancri d), and the first Neptune-sized planets (Gliese 436b and 55 Cancri e).Marcy was a Co-Investigator of the NASA Kepler mission that discovered over 4000 exoplanets, most being smaller than 4 times the size of Earth.His team, led by Erik Petigura and Andrew Howard, showed that approximately 20% of Sun-like stars have a planet of 1–2 times the size of Earth and receive incident stellar light within a factor of 4 of the light the Earth receives from the Sun, making them warm planets, many of which accommodate liquid water.