Ciriaco Goddi1, L. J. Greenhill1, L. D. Matthews1, E. L. M. Humphreys1, C. J. Chandler2
1Harvard-Smithsonian Center for Astrophysics, 2National Radio Astronomy Observatory.
detailed picture of high-mass star formation has remained elusive,
largely owing to difficulties in probing the circumstellar gas around
high-mass young stellar objects (YSOs) at scales 10-100 AU, where
outflows are expected to be launched and collimated by accretion disks.
Radio Source I in Orion BN/KL is the nearest example of a high-mass
YSO, and only one of three YSOs known to power both SiO and H2O masers.
Using VLA and VLBA observations of both maser species, the KaLYPSO
project (http://www.cfa.harvard.edu/kalypso/) aims to overcome past
observational limitations by mapping the structure, 3-D velocity field,
and dynamical evolution of the circumstellar gas 10-1000 AU from Source
I. Based on ~20 epochs of VLBA observations over ~2 years, I will
present a movie of bulk gas flow tracing the compact disk and bipolar
flow from Source I, discuss its relationship to the large-scale
outflows in the BN/KL region, and comment on implications for the
structure of the global star forming region. Assuming that Source I
represents a common stage of high-mass YSO evolution, interpretation of
the 3-D dynamical evolution of Source I will provide unique constraints
on models of high-mass star formation.
The KaLYPSO project is supported by the National Science Foundation under Grant No. NSF AST 0507478.