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Tuesday, 12th May at 3.30pm at the JAC
Pamela Klaassen
ESO, Garching
"Rotation in the Molecular Gas Surrounding HII Regions"
ABSTRACT: If massive stars form in a similar manner to their
lower mass counterparts, disk accretion should play a role. The short
formation timescales of, and large distances to, regions forming
massive stars have made detecting these disks extremely difficult.
There is evidence for disks around some intermediate mass and nearby
young high mass stars suggesting that they can play a role early on.
However, no disks have yet been seen in older high mass star forming
regions - those in which the stars have already begun ionizing their
surroundings.
Here, we present evidence for rotation in the molecular
gas surrounding five HII regions based on SO2 and OCS observations at
arcsecond resolutions with the SMA. From these rotational signatures,
we have derived dynamical masses which are consistent with the gas,
dust and stellar masses we also calculate for these regions from the
same datasets. The size scales are too large for these rotating
structures to be disks, however we will show evidence that the
rotation in these structures is at least marginally stable.
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