spacetoday.net: Multi-planet solar system discovered

Posted: Thu, May 18, 2006, 8:04 AM ET (1204 GMT)
HD 69830 solar system illustration (ESO)

European astronomers have discovered three Neptune-sized exoplanets and a probable asteroid belt orbiting a Sunlike star. In a paper in the Thursday issue of the journal Nature, astronomers reported the discovery of the three exoplanets orbiting the star HD 69830, 41 light-years from Earth. All three have minimum masses of between 10 and 18 Earth masses, making them similar in size to Neptune. The innermost planet is thought to be a rocky world, while the outer two are gas giants; the outermost is at the inner edge of the star's habitability zone, where liquid water could exist. Astronomers also reported evidence of an asteroid belt encircling the star. The discovery was made using a high-resolution spectrograph at the European Southern Observatory, which was able to detect the minute Doppler shifts in the star's spectral lines caused by the planet's gravitational tugs.