Probable detection of H2D+ in the starless core Barnard 68
Abstract
The presence of H2D+ in dense cloud cores underlies ion-molecule reactions that strongly enhance the deuterium fractionation of many molecular species. We determine the H2D+ abundance in one starless core, Barnard 68, that has a particularly well established physical, chemical, and dynamical structure. We observed the ortho-H2D+ ground-state line 1_10-1_11, the N2H+ J=4-3 line, and the H13CO+ 4-3 line with the APEX telescope. We report the probable detection of the o-H2D+ line at an intensity Tmb=0.22 +- 0.08 K and exclusively thermal line width, and find only upper limits to the N2H+ 4-3 and H13CO+ 4-3 intensities. Within the uncertainties in the chemical reaction rates and the collisional excitation rates, chemical model calculations and excitation simulations reproduce the observed intensities and that of o-H2D+ in particular.
Cite
@article{arxiv.astro-ph/0605558,
title = {Probable detection of H2D+ in the starless core Barnard 68},
author = {M. R. Hogerheijde and P. Caselli and M. Emprechtinger and F. F. S. van der Tak and J. Alves and A. Belloche and R. Guesten and A. A. Lundgren and L-A. Nyman and N. Volgenau and M. C. Wiedner},
journal= {arXiv preprint arXiv:astro-ph/0605558},
year = {2009}
}
Comments
APEX A&A special issue, accepted