Tuesday, 10th April 2007 at 3.30pm @ the JAC

ABSTRACT: L183 (also known as L134N) was considered for a long time to be the archetypical dark cloud rich in oxygen that astrochemists used to compare to TMC-1, the carbon-rich sister cloud. Because previous works on this source did not treat radiative transfer with enough care, we found that the column densities of different species derived in these works were not reliable and therefore decided to reconsider the whole problem to provide astrochemists with sound estimates. In the meanwhile, we also studied the dust component, localized two prestellar cores, showed that depletion of gas is present on large scales and concerns all species carrying at least one CNO atom and showed that both the dust and the gas are very cold (7K) in the very center of this cloud. Finally, we are now working on the velocity field of this cloud, which is the reason of my visiting JCMT. This velocity field is again unique : it possibly shows gas flowing to the prestellar core, rotation, and early dissipation of angular momentum. Something unexpected until now. L183 is definitely unique.

Related papers:

Pagani et al. 2003, A&A 406, L59
Pagani et al. 2004, A&A 417, 605
Pagani et al. 2005, A&A 429, 181
Pagani et al. 2007, A&A, "Depletion and low gas temperature in the L183 prestellar core: the N2H+ - N2D+ tool" (astroph/0701823) , in press.