  Circumstellar disks are an essential ingredient of the formation of low-mass
stars. It is unclear, however, whether the accretion-disk paradigm can also
account for the formation of stars more massive than about 10 solar masses, in
which strong radiation pressure might halt mass infall. Massive stars may form
by stellar merging, although more recent theoretical investigations suggest
that the radiative-pressure limit may be overcome by considering more complex,
nonspherical infall geometries. Clear observational evidence, such as the
detection of compact dusty disks around massive young stellar objects, is
needed to identify unambiguously the formation mode of the most massive stars.
Here we report near-infrared interferometric observations that spatially
resolve the astronomical unit-scale distribution of hot material around a
high-mass (approx. 20 solar masses) young stellar object. The image shows an
elongated structure with a size of about 13 x 19 astronomical units, consistent
with a disk seen at an inclination angle of 45 degree. Using geometric and
detailed physical models, we found a radial temperature gradient in the disk,
with a dust-free region less than 9.5 astronomical units from the star,
qualitatively and quantitatively similar to the disks observed in low-mass star
formation. Perpendicular to the disk plane we observed a molecular outflow and
two bow shocks, indicating that a bipolar outflow emanates from the inner
regions of the system.
