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

The processes leading to the birth of low-mass stars such as our Sun have been well studied(1), but the formation of high-mass ( over eight times the Sun's mass, M-.) stars remains poorly understood(2). Recent studies suggest that high-mass stars may form through accretion of material from a circumstellar disk(3), in essentially the same way as low-mass stars form, rather than through the merging of several low-mass stars(4). There is as yet, however, no conclusive evidence(5,6). Here we report the presence of a flattened disk-like structure around a massive 15M(.) 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 M(: 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.