From Prestellar to Protostellar Cores. II. Time Dependence and Deuterium Fractionation

Y. Aikawa Valentine Wakelam 1 F. Hersant 2 R. T. Garrod 3 E. Herbst 4, 5
1 AMOR 2012
L3AB - Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux, OASU - Observatoire aquitain des sciences de l'univers, LAB - Laboratoire d'Astrophysique de Bordeaux [Pessac], Université Sciences et Technologies - Bordeaux 1
2 FORMATION STELLAIRE 2012
L3AB - Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux, OASU - Observatoire aquitain des sciences de l'univers, LAB - Laboratoire d'Astrophysique de Bordeaux [Pessac], Université Sciences et Technologies - Bordeaux 1
Abstract : We investigate the molecular evolution and D/H abundance ratios that develop as star formation proceeds from a dense molecular cloud core to a protostellar core, by solving a gas-grain reaction network applied to a one-dimensional radiative hydrodynamic model with infalling fluid parcels. Spatial distributions of gas and ice-mantle species are calculated at the first-core stage, and at times after the birth of a protostar. Gas-phase methanol and methane are more abundant than CO at radii r <~ 100 AU in the first-core stage, but gradually decrease with time, while abundances of larger organic species increase. The warm-up phase, when complex organic molecules are efficiently formed, is longer-lived for those fluid parcels infalling at later stages. The formation of unsaturated carbon chains (warm carbon-chain chemistry) is also more effective in later stages; C+, which reacts with CH4 to form carbon chains, increases in abundance as the envelope density decreases. The large organic molecules and carbon chains are strongly deuterated, mainly due to high D/H ratios in the parent molecules, determined in the cold phase. We also extend our model to simulate simply the chemistry in circumstellar disks, by suspending the one-dimensional infall of a fluid parcel at constant disk radii. The species CH3OCH3 and HCOOCH3 increase in abundance in 104-105 yr at the fixed warm temperature; both also have high D/H ratios.
Liste complète des métadonnées

https://hal.archives-ouvertes.fr/hal-00764165
Contributeur : Marie-Paule Pomies <>
Soumis le : mercredi 12 décembre 2012 - 14:56:36
Dernière modification le : mercredi 27 juillet 2016 - 14:48:48

Identifiants

Collections

Citation

Y. Aikawa, Valentine Wakelam, F. Hersant, R. T. Garrod, E. Herbst. From Prestellar to Protostellar Cores. II. Time Dependence and Deuterium Fractionation. Astrophysical Journal, American Astronomical Society, 2012, 760, pp.40. 〈10.1088/0004-637X/760/1/40〉. 〈hal-00764165〉

Partager

Métriques

Consultations de la notice

163