Posted: Wed, Sep 18, 2002, 6:46 AM ET (1046 GMT)
Astronomers announced Tuesday that they have discovered what they believe is the 100th extrasolar planet. The planet, 1.2 times the mass of Jupiter, has a near circular orbit 2.5 AU (375 million km) from the star Tau 1 Gruis. The planet is one of the first Jupiter analogs — planets with masses and orbits similar to Jupiter — discovered. Astronomers announcing the discovery said it was the 100th exoplanet found since the first exoplanet around a Sunlike star was found seven years ago, although the exact number of exoplanets varies from survey to survey. The number of exoplanets found is now allowing scientists to calculate statistics on the types of solar systems, and the fraction of stars with planets: about 12 percent have planets within 5 AU, according to planet hunters Geoff Marcy and Paul Butler.

Related Links:

•  Spaceflight Now article
•  SPACE.com article
•  Reuters article