The N2D+/N2H+ ratio as an evolutionary tracer of Class 0 protostars
| Autor: | Emprechtinger, M., Caselli, P., Volgenau, N. H., Stutzki, J., Wiedner, M. C. |
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| Rok vydání: | 2008 |
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| Druh dokumentu: | Working Paper |
| DOI: | 10.1051/0004-6361:200810324 |
| Popis: | 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. Comment: 19 pages, 12 figures, accepted by A&A |
| Databáze: | arXiv |
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