Astronomy Picture of the Day

Discover the cosmos! Each day we feature a different image or photograph of our fascinating universe, along with a brief explanation written by a professional astronomer.

December 1, 1995

51 Pegasi: A New Planet Discovered
Credit: UK Schmidt Telescope, Skyview
Copyright: Royal Observatory Edinburgh, Anglo-Australian Observatory, and AURA

Explanation: Are we alone in the universe? Do other stars have planets too? Humanity took one step closer to answering these questions in October 1995 when it was announced that the star 51 Pegasi harbors at least one planet. In the above picture of 51 Peg the planet is not visible - it can only be detected by noticing small changes in the star's motion. Claims of planets orbiting other stars are rare, with perhaps the most credible pertaining to a neutron star - a star much different than the Sun. But new ground was broken when the planetary detection claimed around the normal Sun-like star 51 Peg was confirmed. The planet, discovered by Michel Mayor and Didier Queloz, is thought to be like Jupiter - except orbiting so close to the parent star that it's year lasts only about 4 days! In the above picture the lines centered on 51 Peg are caused by the telescope itself and are not related to the star or planet.

Tomorrow's picture: Lightning Below

Authors & editors: Robert Nemiroff (GMU) & Jerry Bonnell (USRA).
NASA Technical Rep.: Sherri Calvo. Specific rights apply.
A service of: LHEA at NASA/ GSFC