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arXiv · 0809.3759

The N2D+/N2H+ ratio as an evolutionary tracer of Class 0 protostars

M. Emprechtinger·P. Caselli·N. H. Volgenau·J. Stutzki·M. C. Wiedner
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Abstract

Deuterated ions are abundant in cold (T=10 K), dense (n=10^5 cm^-3) regions, in which CO is frozen out onto dust grains. In such environments, the deuterium fractionation of such ions can exceed the elemental abundance ratio of D/H by a factor of 10^4. In this paper we use the deuterium fractionation to investigate the evolutionary state of Class 0 protostars. In a sample of 20 protostellar objects, we found a clear correlation between the N2D+/N2H+ ratio and evolutionary tracers. As expected, the coolest, i.e. the youngest, objects show the largest deuterium fractionation. Furthermore, we find that sources with a high N2D+/N2H+ ratio show clear indication for infall.

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M. Emprechtinger, P. Caselli, N. H. Volgenau, J. Stutzki, M. C. Wiedner. 2008-09-22. The N2D+/N2H+ ratio as an evolutionary tracer of Class 0 protostars. https://doi.org/10.1051/0004-6361%3A200810324

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