Astronomy and Astrophysics – Astrophysics
Scientific paper
2007-05-02
Astronomy and Astrophysics
Astrophysics
5 pages, 4 figures, accepted by ApJL
Scientific paper
At the high densities and low temperatures found in star forming regions, all molecules other than H2 should stick on dust grains on timescales shorter than the cloud lifetimes. Yet these clouds are detected in the millimeter lines of gaseous CO. At these temperatures, thermal desorption is negligible and hence a non-thermal desorption mechanism is necessary to maintain molecules in the gas phase. Here, the first laboratory study of the photodesorption of pure CO ice under ultra high vacuum is presented, which gives a desorption rate of 3E-3 CO molecules per UV (7-10.5 eV) photon at 15 K. This rate is factors of 1E2-1E5 larger than previously estimated and is comparable to estimates of other non-thermal desorption rates. The experiments constrains the mechanism to a single photon desorption process of ice surface molecules. The measured efficiency of this process shows that the role of CO photodesorption in preventing total removal of molecules in the gas has been underestimated.
Awad Zainab
Fraser Helen Jane
Fuchs Guido W.
Linnartz Harold
Oberg Karin I.
No associations
LandOfFree
Photodesorption of CO ice 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 Photodesorption of CO ice, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Photodesorption of CO ice will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-674579