spacetoday.net: Up to seven planets found around star

Posted: Wed, Aug 25, 2010, 8:38 AM ET (1238 GMT)
HD10180 exoplanet illustration (ESO)

Astronomers announced Tuesday that they have found as many as seven planets orbiting a Sun-like star, the most planets found to date discovered around a star other than our Sun. Astronomers using a sensitive spectrograph attached to a 3.6-meter telescope operated by the European Southern Observatory in Chile confirmed the presence of at least five planets similar in size to Neptune, with masses between 13 and 25 times that of the Earth, orbiting the star HD 10180, 127 light-years away. Those planets are orbiting at distances between 0.06 and 1.4 astronomical units. Astronomers also believe there may be two other planets around the same star: a larger one roughly the size of Saturn with an orbital period of six years, and one as small as 1.4 Earth masses with an orbital period of just over one day. That planet, if confirmed, would be the smallest exoplanet yet discovered around a Sun-like star. The team detected the planets using the radial velocity technique, measuring Doppler shifts in the star's spectral lines causes by the wobble created by the orbiting planets' gravitational pull.