Control Number
2008
Presentation Preference
Oral
Title
3-d Dynamical Evolution Of The High-mass Young Stellar Object
Source I In Orion Bn/kl On Scales 10-100 Au As Traced By Sio Masers
Author Block
Ciriaco Goddi1, L. J. Greenhill1, L. D. Matthews1, E. L. M. Humphreys1, C. J. Chandler2
1Harvard-Smithsonian Center for Astrophysics, 2National Radio Astronomy Observatory.
Category
18. Star Formation
A 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.
 

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