Chemical modeling of L183 (L134N): an estimate of the ortho/para H{_2} ratio
| hal.structure.identifier | Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique [LERMA] | |
| dc.contributor.author | PAGANI, L. | |
| hal.structure.identifier | Centre d'étude spatiale des rayonnements [CESR] | |
| hal.structure.identifier | Centre d'étude spatiale des rayonnements [CESR] | |
| dc.contributor.author | VASTEL, C. | |
| hal.structure.identifier | Technologies et systèmes d'information pour les agrosystèmes [UR TSCF] | |
| dc.contributor.author | HUGO, E. | |
| hal.structure.identifier | Laboratoire Aimé Cotton [LAC] | |
| hal.structure.identifier | Department of Physics [Orlando] [UCF | Physics] | |
| dc.contributor.author | KOKOOULINE, V. | |
| dc.contributor.author | GREENE, C. H. | |
| hal.structure.identifier | Laboratoire d'Astrophysique de Grenoble [LAOG] | |
| hal.structure.identifier | Laboratoire d'Astrophysique de Bordeaux [Pessac] [LAB] | |
| hal.structure.identifier | Observatoire aquitain des sciences de l'univers [OASU] | |
| hal.structure.identifier | Université Sciences et Technologies - Bordeaux 1 [UB] | |
| dc.contributor.author | BACMANN, A. | |
| hal.structure.identifier | Laboratoire de Radioastronomie [LRA] | |
| dc.contributor.author | BAYET, Estelle | |
| hal.structure.identifier | Laboratoire d'Astrophysique de Grenoble [LAOG] | |
| dc.contributor.author | CECCARELLI, C. | |
| dc.contributor.author | PENG, R. | |
| hal.structure.identifier | I. Physikalisches Institut [Köln] | |
| dc.contributor.author | SCHLEMMER, S. | |
| dc.date.issued | 2009-02 | |
| dc.identifier.issn | 0004-6361 | |
| dc.description.abstractEn | Context: The high degree of deuteration observed in some prestellar cores depends on the ortho-to-para H2 ratio through the H3+ fractionation. Aims: We want to constrain the ortho/para H2 ratio across the L183 prestellar core. This is required to correctly describe the deuteration amplification phenomenon in depleted cores such as L183 and to relate the total (ortho+para) H2D+ abundance to the sole ortho-H2D+ column density measurement. Methods: To constrain this ortho/para H2 ratio and derive its profile, we make use of the N2D^+/N2H+ ratio and of the ortho-H2D+ observations performed across the prestellar core. We use two simple chemical models limited to an almost totally depleted core description. New dissociative recombination and trihydrogen cation-dihydrogen reaction rates (including all isotopologues) are presented in this paper and included in our models. Results: We estimate the H2D+ ortho/para ratio in the L183 cloud, and constrain the H2 ortho/para ratio: we show that it varies across the prestellar core by at least an order of magnitude, being still very high (≈0.1) in most of the cloud. Our time-dependent model indicates that the prestellar core is presumably older than 1.5-2 × 105 years but that it may not be much older. We also show that it has reached its present density only recently and that its contraction from a uniform density cloud can be constrained. Conclusions: A proper understanding of deuteration chemistry cannot be attained without taking into account the whole ortho/para family of molecular hydrogen and trihydrogen cation isotopologues as their relations are of utmost importance in the global scheme. Tracing the ortho/para H2 ratio should also place useful constraints on the dynamical evolution of prestellar cores. Appendices A and B are only available in electronic form at http://www.aanda.org | |
| dc.language.iso | en | |
| dc.publisher | EDP Sciences | |
| dc.subject.en | ISM: abundances | |
| dc.subject.en | ISM: clouds | |
| dc.subject.en | ISM: structure | |
| dc.subject.en | astrochemistry | |
| dc.subject.en | ISM: individual objects: L183 | |
| dc.subject.en | molecular processes | |
| dc.title.en | Chemical modeling of L183 (L134N): an estimate of the ortho/para H{_2} ratio | |
| dc.type | Article de revue | |
| dc.identifier.doi | 10.1051/0004-6361:200810587 | |
| dc.subject.hal | Planète et Univers [physics]/Astrophysique [astro-ph]/Astrophysique galactique [astro-ph.GA] | |
| dc.subject.hal | Physique [physics]/Astrophysique [astro-ph]/Astrophysique galactique [astro-ph.GA] | |
| dc.identifier.arxiv | 0810.1861 | |
| bordeaux.journal | Astronomy and Astrophysics - A&A | |
| bordeaux.page | 623-636 | |
| bordeaux.volume | 494 | |
| bordeaux.peerReviewed | oui | |
| hal.identifier | hal-00633468 | |
| hal.version | 1 | |
| hal.popular | non | |
| hal.audience | Internationale | |
| hal.origin.link | https://hal.archives-ouvertes.fr//hal-00633468v1 | |
| bordeaux.COinS | ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Astronomy%20and%20Astrophysics%20-%20A&A&rft.date=2009-02&rft.volume=494&rft.spage=623-636&rft.epage=623-636&rft.eissn=0004-6361&rft.issn=0004-6361&rft.au=PAGANI,%20L.&VASTEL,%20C.&HUGO,%20E.&KOKOOULINE,%20V.&GREENE,%20C.%20H.&rft.genre=article |
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