Control Number |
1766 |
Presentation Preference |
Poster |
Title |
Proper Motions of the SiO Masers Surrounding the Young Stellar Object Orion Source I |
Author Block |
Lynn D. Matthews1, C. Goddi1, L. J. Greenhill1, C. J. Chandler2, E. M. L. Humphreys1, M. J. Reid1 1Harvard-Smithsonian, CfA, 2National Radio Astronomy Observatory. |
Category |
18. Star Formation |
Investigations
of the dynamics of material <100 AU from high mass young stellar
objects (YSOs) are crucial for constraining models of high mass star
formation. These are the scales over which accretion is expected to
occur and over which outflows are expected to be launched and
collimated. As part of the KaLYPSO project
(http://www.cfa.harvard.edu/kalypso), our group has been using Very
Baseline Array (VLBA) observations of SiO v=1 & 2, J=1-0 masers to
investigate gas motions within 10-100 AU of the nearest high-mass YSO,
Source I in the Orion BN/KL region. We will present proper motion
measurements of SiO maser spots based on 19 epochs of data spanning a
22-month period. We find maser spots that persist up to several months
and whose motions in the plane of the sky range from ~1-20 km/s. The
observed spot motions indicate both rotation and outflow/expansion of
the molecular gas surrounding Source I. Our results support a picture
in which the SiO masers arise either from a flared, rotating, disk seen
nearly edge-on, or the interface between a disk and an expanding
wind/outflow oriented along the northeast/southwest direction. This work is funded by grant 0507478 from the National Science Foundation. |
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