A disk of dust and molecular gas around a high-mass protostar

Abstract

The processes leading to the birth of low-mass stars such as our Sun have been well studied1, but the formation of high-mass (over eight times the Sun's mass, Mcircle dot) stars remains poorly understood2. Recent studies suggest that high-mass stars may form through accretion of material from a circumstellar disk3, in essentially the same way as low-mass stars form, rather than through the merging of several low-mass stars4. There is as yet, however, no conclusive evidence5, 6. Here we report the presence of a flattened disk-like structure around a massive 15M circle dot protostar in the Cepheus A region, based on observations of continuum emission from the dust and line emission from the molecular gas. The disk has a radius of about 330 astronomical units (au) and a mass of 1 to 8 Mcircle dot. It is oriented perpendicular to, and spatially coincident with, the central embedded powerful bipolar radio jet, just as is the case with low mass stars, from which we conclude that high-mass stars can form through accretion.