Astronomy and Astrophysics – Astrophysics
Scientific paper
2004-02-20
Astron.Astrophys. 418 (2004) 1035-1043
Astronomy and Astrophysics
Astrophysics
Accepted for Astronomy and Astrophysics, 22 Pages, 9 Figures
Scientific paper
10.1051/0004-6361:20035718
We have carried out calculations of ionization equilibrium and deuterium fractionation for conditions appropriate to a completely depleted, low mass pre--protostellar core, where heavy elements such as C, N, and O have vanished from the gas phase and are incorporated in ice mantles frozen on dust grain surfaces. We put particular emphasis on the interpretation of recent observations of H2D+ towards the centre of the prestellar core L1544 (Caselli et al. 2003) and also compute the ambipolar diffusion timescale. We consider explicitly the ortho and para forms of H2,H3+, and H2D+. Our results show that the ionization degree under such conditions depends sensitively on the grain size distribution or, more precisely, on the mean grain surface area per hydrogen nucleus. Depending upon this parameter and upon density, the major ion may be H+, H3+, or D3+. We show that the abundance of ortho-H2D+ observed towards L1544 can be explained satisfactorily in terms of a complete depletion model and that this species is, as a consequence, an important tracer of the kinematics of prestellar cores.
des Forets Guillaume Pineau
Flower David R.
Walmsley Charles Malcolm
No associations
LandOfFree
Complete Depletion in prestellar cores 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 Complete Depletion in prestellar cores, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Complete Depletion in prestellar cores will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-709093