Astronomy and Astrophysics – Astronomy
Scientific paper
Nov 1996
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1996apj...471..871a&link_type=abstract
Astrophysical Journal v.471, p.871
Astronomy and Astrophysics
Astronomy
12
Ism: H Ii Regions, Ism: Abundances, Ism: Individual Alphanumeric: W3, Radio Lines: Ism
Scientific paper
We present high-sensitivity images of the H92α, He92α, and C92α recombination line emission from H II regions in the Galactic radio source W3. Our 8.3 GHz VLA observations have 4" resolution and sufficient sensitivity to image the carbon recombination line in four of the eight H II regions in the complex. Portions of W3A, the largest and probably most evolved of the H II regions, have a helium abundance as high as 20% by number (nearly twice the cosmic abundance) which confirms previous observations made with lower signal-to-noise ratios. W3A also shows large velocity gradients in the H92α line; we conclude that the gradient is probably caused by the evaporation of the dense molecular core associated with IRS 5. Near the edges of W3B and W3C, strong C+ emission is found where no hydrogen or helium line emission is detected. This C+ emission comes from the interface zone between the H II region and the surrounding molecular cloud. We show that the C+ velocity is more typical of the surrounding molecular cloud while the H+ and He+ velocities trace the ionized gas. A H92α velocity gradient is used as a probe of the gasdynamics in W3B; a model is proposed which explains the gradient. Despite the fact that W3C and W3D are separate H II regions, they apparently share a common C+ region; the C92α line intensity is up to 70% that of the H92α line. Three independent methods provide an electron temperature in the range of Te = 8000-9000 K for W3A; a wider range of values is derived for W3B and W3D. W3B shows signs (1O σ) of a decreasing radial electron temperature gradient.
Adler David S.
Goss William Miller
Wood Douglas O. S.
No associations
LandOfFree
Helium Enrichment and Carbon Ionization in the W3 Core 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 Helium Enrichment and Carbon Ionization in the W3 Core, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Helium Enrichment and Carbon Ionization in the W3 Core will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1146372