spacetoday.net: Astronomers discover youngest exoplanet

Posted: Thu, Jan 3, 2008, 7:47 AM ET (1247 GMT)
TW Hydrae exoplanet illustration (MPIA)

German astronomers reported this week that they have discovered the youngest extrasolar planet found to date, a world that is still embedded within the protoplanetary disk around its star. Astronomers detected the presence of the exoplanet surrounding the star TW Hydrae indirectly, using the radial velocity technique used to find most of the over 250 known exoplanets. The star itself is estimated to be only 8-10 million years old, and is still surrounded by a protoplanetary disk of dust and gas. The planet, about 10 times the mass of Jupiter, orbits in an inner gap in the disk, completing one orbit in just over 3.5 days. The discovery puts new constraints on how long it takes for planets to form around new stars.