Astronomy and Astrophysics – Astronomy
Scientific paper
Feb 2000
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000apj...529l.111c&link_type=abstract
The Astrophysical Journal, Volume 529, Issue 2, pp. L111-L114.
Astronomy and Astrophysics
Astronomy
30
Ism: Abundances, Ism: Clouds, Ism: Molecules, Molecular Processes
Scientific paper
We consider the gas-phase chemistry of CO2 molecules in active regions. We show that CO2 molecules evaporated from dust in hot cores cannot be efficiently destroyed and are in fact copiously produced in cooler gas. When CO2-rich ices are sputtered in strong MHD shock waves, the increase in atomic hydrogen, due to H2 dissociation by ion-neutral streaming, means that CO2 can be depleted by factors of ~500 from its injected abundance. We find that a critical shock speed exists at higher preshock densities below which CO2 molecules can be efficiently sputtered but survive in the postshock gas. These calculations offer an explanation for the low gas/solid CO2 ratios detected by the Infrared Space Observatory in star-forming cores as being due to shock destruction followed by partial reformation in warm gas. The presence of high abundances of CO2 in the strongly shocked Galactic center clouds Sgr B2 and Sgr A also find a tentative explanation in this scenario. Shock activity plays an important role in determining the chemistry of star-forming regions, and we suggest that most hot cores are in fact shocked cores.
Charnley Steven B.
Kaufman Michael J.
No associations
LandOfFree
Carbon Dioxide in Star-forming Regions 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 Carbon Dioxide in Star-forming Regions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Carbon Dioxide in Star-forming Regions will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1492307