ogre7299 writes "Astronomers have found direct evidence of a forming proto-solar system and 'weighed' the forming star for the first time The results were reported in Nature (abstract) and the pre-print is available at the arXiv. 'The star, called L1527 IRS, is only one-fifth the mass of the sun, and is expected to keep growing as the swirling disk of matter surrounding it falls into its surface. Astronomers estimated the star formed around the same time that Neanderthals evolved on Earth: just 300,000 years ago. ... Generally, a star forms from a cloud of gas that collapses into itself. Material streams inward from the cloud and forms a protostar in the center of a disk of gas and dust. Over millions of years, material falls on the protostar and releases quite a bit of energy. In L1527, 90 percent of its energy comes from material landing on the surface of the protostar. The remaining 10 percent comes from the star itself.' Measurements for the research came from the Submillimeter Array and the Combined Array for Research in Millimeter-wave Astronomy."