Very Small HII Regions Embedded in Massive Accretion Flows

Details Very Small HII Regions Embedded in Massive Accretion Flows Very Small HII Regions Embedded in Massive Accretion Flows

Jan 2010

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010aas...21531901g&link_type=abstract

American Astronomical Society, AAS Meeting #215, #319.01; Bulletin of the American Astronomical Society, Vol. 42, p.320

Astronomy and Astrophysics

Astronomy

Scientific paper

We present preliminary results of an SMA+VLA study of a small sample of hypercompact HII regions with evidence of accretion flows surrounding them. Molecular-line observations at a resolution of a few arcseconds reveal motions in the natal cores indicative of rotation, infall, and/or outflow at subparsec scales. Sub-arcsecond resolution data often reveal the presence of a small group of massive (proto)stars, usually at different evolutionary stages. The hypercompact HII regions with positive spectral index from cm to mm wavelengths are the smallest and most embedded, and modeling indicates the presence of density gradients in the ionized gas. Their flattened molecular envelopes show evidence of rotation, infall, and/or outflow at scales < 10 000 AU. In the inner few 1000 AU the ionized gas is found to have organized motions, probably in the form of rotation and/or outflow. Multiepoch observations of the free-free continuum reveal large flux variations in timescales of years, attributable to interactions with the surrounding molecular gas. All these observations favor a picture in which: i) massive (O stars, M>20 Msun) form by accretion; ii) accretion can continue past the onset of an HII region; iii) the HII region is kept confined by its own molecular accretion flow for a period of time.
R. G.-M. acknowledges support from SAO and ASIAA through an SMA predoctoral fellowship.

Affiliated with

Also associated with

No associations

Rating

Very Small HII Regions Embedded in Massive Accretion Flows does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Very Small HII Regions Embedded in Massive Accretion Flows, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Very Small HII Regions Embedded in Massive Accretion Flows will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-961827