High Quality Content by WIKIPEDIA articles! Upsilon Andromedae d is an extrasolar planet orbiting the Sun-like star Upsilon Andromedae A. Its discovery in April 1999 by Geoffrey Marcy and R. Paul Butler made Upsilon Andromedae the first star (other than the pulsar PSR 1257+12 and the Sun) to be known to host a multiple-planet planetary system. Upsilon Andromedae d is the third planet from its star in order of distance and the outermost known planet in its planetary system.