51 Pegasi B. Artist's impression of the planet 51 Pegasi B orbiting its sun, 51 Pegasi. Two moons can be seen against the planet. This planet was discovered in 1995 by Michel Mayor and Didier Queloz of Geneva Observatory, Italy. The star is a Sun-like star some 42 light years from Earth. The planet is about half as massive as Jupiter, and orbits only 7 million km from the star, equivalent to 1/6th of Mercury's orbit around the Sun. The surface temperature is probably over 1000 Celsius, and the rocks of the planet at least partly molten. The planet possibly has one side which permanently faces the star.