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| EPoS Contribution |
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CN, HCN, and HNC at high densities in prestellar cores
C. Malcolm Walmsley INAF, Osservatorio di Arcetri, Florence, Italy | |
| In order to understand the kinematics of prestellar cores, one needs tracers that remain in the gas phase at high density in spite of the tendency of many species to freeze out onto dust grain surfaces. We have been recently studying the properties of CN, HCN, and HNC from this point of view and I will report on the results. In some objects, these species seem to remain in the gas phase at densities above those at which CO disappears suggesting that a small fraction of CO remains in the gas phase at densities around 100000 cm-3. Also, the CN/HCN abundance ratio seems to remain of order unity independent of density in confict with theoretical expectations. These properties moreover seem to vary from source to source suggesting that another parameter (age?) is important as well as density and temperature. Our modelling suggests also that the fraction of nitrogen in solid form is likely large in many cores and this poses the problem of what form such nitrogen ice takes. | |
| Collaborators: P. Hily-Blant , LAOG, Grenoble, France M. Padovani, Arcetri Observatory, Italy (now Barcelona) G. Pineau des Forets, IAS, Paris, France D. Flower, Univ. Durham, UK |
Key publication
Suggested Session: Chemistry, Cores and Collapse, Magnetic Fields |