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.

arXiv commentAPEX A&A special issue, accepted

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Cited by in corpus (7)

• Survey of ortho-H2D+(1_{1,0}-1_{1,1}) in dense cloud cores
• Chemistry in Disks. IX. Observations and modeling of HCO+ and DCO+ in DM Tau
• The Ionization Fraction of Barnard 68: Implications for Star and Planet Formation
• Far-Infrared detection of H2D+ toward Sgr B2
• A computed line list for the H2D+ molecular ion
• H${}_2$D${}^{+}$ line emission in Proto-Planetary Disks
• Terahertz and Far-Infrared Windows Opened at Dome A, Antarctica