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Hydrodynamical-Chemical Models from Prestellar Cores to Protostellar Cores

hal.structure.identifierDepartment of Earth and Planetary Sciences [Kobe]
dc.contributor.authorAIKAWA, Yuri
dc.contributor.authorFURUYA, Kenji
hal.structure.identifieraMOR 2011
dc.contributor.authorWAKELAM, Valentine
hal.structure.identifierFORMATION STELLAIRE 2011
dc.contributor.authorHERSANT, F.
dc.contributor.authorMATSUMOTO, Tomoaki
dc.contributor.authorSAIGO, Kazuya
dc.contributor.authorTOMIDA, Kengo
dc.contributor.authorTOMISAKA, Koji
dc.contributor.authorGARROD, Robin
hal.structure.identifierDepartment of Physics [OHIO STATE UNIVERSITY]
hal.structure.identifierDepartments of Astronomy and Chemistry
dc.contributor.authorHERBST, Eric
dc.date.issued2011-12
dc.date.conference2011
dc.description.abstractEnWe investigate the molecular evolution in star forming cores from dense cloud cores (nH ~ 104 cm-3, T ~ 10 K) to protostellar cores. A detailed gas-grain reaction network is solved in infalling fluid parcels in 1-D radiation hydrodynamic model. Large organic molecules are mainly formed via grain-surface reaction at T ~ several 10 K and sublimated to the gas-phase at ~ 100 K, while carbon-chain species are formed at a few 10 K after the sublimation of CH4 ice. The former accounts for the high abundance of large organic molecules in hot corinos such as IRAS16293, and the latter accounts for the carbon chain species observed toward L1527. The relative abundance of carbon chain species and large organic species would depend on the collapse time scale and/or temperature in the dense core stage. The large organic molecules and carbon chains in the protostellar cores are heavily deuterated; although they are formed in the warm temperatures, their ingredients have high D/H ratios, which are set in the cold core phase and isothermal collapse phase. HCOOH is formed by the gas-phase reaction of OH with the sublimated H2CO, and is further enriched in Deuterium due to the exothermic exchange reaction of OH + D -> OD + H. In the fluid parcels of the 1-D collapse model, warm temperature T. ~ several 10 K lasts for only ~ 104 yr, and the fluid parcels fall to the central star in ~ 100 yr after the temperature of the parcel rises to T >= 100 K. These timescales are determined by the size of the warm region and infall (~ free-fall) velocity: rwarm/tff. In reality, circum stellar disk is formed, in which fluid parcels stay for a longer timescale than the infall timescale. We investigate the molecular evolution in the disk by simply assuming that a fluid parcel stays at a constant temperature and density (i.e. a fixed disk radius) for 104 - 105 yrs. We found that some organic species which are underestimated in our 1-D collapse model, such as CH3OCH3 and HCOOCH3, become abundant in the disk. We also found that these disk species have very high D/H ratio as well, since their ingredients are highly deuterated. Finally we investigate molecular evolution in a 3D hydrodynamic simulation of star forming core. We found CH3OH are abundant in the vicinity of the first core. The abundances of large organic species are determined mainly by the local temperature (sublimation), because of the short lifetime of the first core and the efficient mass accretion via angular momentum transfer.
dc.language.isoen
dc.source.title2011IAUS..280...33A The Molecular Universe, Proceedings of the International Astronomical Union, IAU Symposium, Volume 280, p. 33-42, 2012
dc.subject.enstars: formation
dc.subject.enISM: clouds
dc.subject.enISM: abundances
dc.typeCommunication dans un congrès
dc.identifier.doi10.1017/S1743921311024847
dc.subject.halPlanète et Univers [physics]/Astrophysique [astro-ph]/Cosmologie et astrophysique extra-galactique [astro-ph.CO]
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]/Cosmologie et astrophysique extra-galactique [astro-ph.CO]
bordeaux.page33-42
bordeaux.volume280
bordeaux.countryES
bordeaux.title.proceeding2011IAUS..280...33A The Molecular Universe, Proceedings of the International Astronomical Union, IAU Symposium, Volume 280, p. 33-42, 2012
bordeaux.conference.cityTolede
bordeaux.peerReviewedoui
hal.identifierhal-00665011
hal.version1
hal.invitednon
hal.proceedingsoui
hal.popularnon
hal.audienceInternationale
dc.title.itHydrodynamical-Chemical Models from Prestellar Cores to Protostellar Cores
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-00665011v1
bordeaux.COinSctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.btitle=2011IAUS..280...33A%20The%20Molecular%20Universe,%20Proceedings%20of%20the%20International%20Astronomical%20Union,%20IAU%20Symposium,%20Volume%20280,%20p.%2033-42,%20201&rft.date=2011-12&rft.volume=280&rft.spage=33-42&rft.epage=33-42&rft.au=AIKAWA,%20Yuri&FURUYA,%20Kenji&WAKELAM,%20Valentine&HERSANT,%20F.&MATSUMOTO,%20Tomoaki&rft.genre=unknown


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