2000A&A...359.1169L -
Astronomy and Astrophysics, volume 359, 1169-1174 (2000/7-3)
The enormous abundance of D2CO in IRAS 16293-2422.
LOINARD L., CASTETS A., CECCARELLI C., TIELENS A.G.G.M., FAURE A., CAUX E. and DUVERT G.
Abstract (from CDS):
Ceccarelli et al. (
1998A&A...338L..43C) recently reported the detection of D
2CO in the low-luminosity protostar IRAS 16293-2422. Using the data available at the time, they found that the abundance of D
2CO might be as high as 1/10th that of its hydrogenated counterpart H
2CO. Here we describe and analyse new multi-transition observations of D
2CO, HDCO, H
2CO, and H
213CO towards IRAS 16293-2422. Correcting for the opacity of the H
2CO lines, we find that the abundance of D
2CO is ∼5% that of H
2CO. In addition, we find a component in absorption - also associated to IRAS 16293-2422, but at larger radius - where the abundance of D
2CO compared to H
2CO could be even higher. Though slightly lower than initially claimed, the abundance of D
2CO in IRAS 16293-2422 is extremely high, more than one order of magnitude higher than in Orion KL, the only other source where D
2CO has ever been detected. Because the gas temperature (T=20-50K) is too high, deuteration in the gas-phase is very insufficient to explain such high abundances. We conclude that D
2CO is most likely not currently formed in the gas phase, but is evaporated from the dust grains, where it has been accumulating during the cold, dense pre-collapse period.
Abstract Copyright:
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Journal keyword(s):
stars: formation - ISM: abundances - ISM: molecules - ISM: individual objects: IRAS 16293-2422
Simbad objects:
1
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