  (abbreviated) We investigate the spatial structure and spectral energy
distribution of an edge-on circumstellar disk around an optically invisible
young stellar object that is embedded in a dark cloud in the Carina Nebula.
Whereas the object was detected as an apparently point-like source in earlier
infrared observations, only the superb image quality (FWHM ~0.5") of our VLT /
HAWK-I data could reveal, for the first time, its peculiar morphology. It
consists of a very red point-like central source that is surrounded by a
roughly spherical nebula, which is intersected by a remarkable dark lane
through the center. We construct the spectral energy distribution of the object
from 1 to 870 microns and perform a detailed radiative transfer modeling of the
spectral energy distribution and the source morphology. The observed object
morphology in the near-IR images clearly suggests a young stellar object that
is embedded in an extended, roughly spherical envelope and surrounded by a
large circumstellar disk with a diameter of ~5500 AU that is seen nearly
edge-on. The radiative transfer modeling shows that the central object is a
massive (10-15 Msun) young stellar object. The circumstellar disk has a mass of
about 2 Msun. The disk object in Carina is one of the most massive young
stellar objects for which a circumstellar disk has been detected so far, and
the size and mass of the disk are very large compared to the corresponding
values found for most other similar objects.
