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HCNH+ abundance in cold dense clouds based on the first hyperfine resolved rate coefficients

hal.structure.identifierInstitut de Physique de Rennes [IPR]
dc.contributor.authorBOP, Cheikh T.
hal.structure.identifierConsejo Superior de Investigaciones Científicas [Spain] [CSIC]
dc.contributor.authorAGÚNDEZ, Marcelino
hal.structure.identifierConsejo Superior de Investigaciones Científicas [Spain] [CSIC]
dc.contributor.authorCERNICHARO, Jose
hal.structure.identifierLaboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
dc.contributor.authorLEFLOCH, Bertrand
hal.structure.identifierInstitut de Physique de Rennes [IPR]
dc.contributor.authorLIQUE, François
dc.date.accessioned2024-04-16T02:24:01Z
dc.date.available2024-04-16T02:24:01Z
dc.date.issued2024
dc.identifier.issn0004-6361
dc.identifier.urihttps://oskar-bordeaux.fr/handle/20.500.12278/199030
dc.description.abstractEnThe protonated form of hydrogen cyanide, HCNH+, holds significant importance in astrochemistry, serving as an intermediate species in ion-neutral reactions occurring in the cold molecular clouds. Although it plays a crucial role in the chemistry of HCN and HNC, the excitation rate coe fficients of this molecular cation by the dominant interstellar colliders have not been thoroughly investigated, leading to limitations in the radiative transfer models used to derive its abundance. In this work, we present the first hyperfine-resolved excitation rate coe fficients for HCNH+ induced by collisions with both He and H-2 at low temperatures, addressing a crucial requirement for precise modeling of HCNH+ abundance in typical cold dense molecular clouds. Using non-local thermodynamic equilibrium (non-LTE) radiative transfer calculations, we reproduced the 1 -> 0 and 2 -> 1 observational spectra of HCNH+ fairly well and derived updated molecular column densities. For the TMC-1 molecular cloud, the new HCNH+ abundance is twice as large as suggested by previous LTE modeling, whereas the column density of this molecular cation is improved only by 10% in the case of the L483 proto-star. The factor of two in the case of TMC-1 most likely arises from an error in the early analysis of observational spectra rather than an effect of the LTE assumption, given that the HCNH+ lines are predominantly thermalized at densities higher than 2 x 10(4) cm(-3). For multiline studies of clouds of moderate densities, we strongly recommend using the collisional rate coe fficients reported in this work.
dc.language.isoen
dc.publisherEDP Sciences
dc.subject.enmolecular data
dc.subject.enmolecular processes
dc.subject.enradiative transfer
dc.subject.enscattering
dc.subject.enISM: abundances
dc.subject.enISM: molecules
dc.title.enHCNH+ abundance in cold dense clouds based on the first hyperfine resolved rate coefficients
dc.typeArticle de revue
dc.identifier.doi10.1051/0004-6361/202348947
dc.subject.halPhysique [physics]
bordeaux.journalAstronomy and Astrophysics - A&A
bordeaux.pageL19
bordeaux.volume681
bordeaux.hal.laboratoriesLaboratoire d'Astrophysique de Bordeaux (LAB) - UMR 5804*
bordeaux.institutionUniversité de Bordeaux
bordeaux.institutionCNRS
bordeaux.peerReviewedoui
hal.identifierhal-04512657
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-04512657v1
bordeaux.COinSctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Astronomy%20and%20Astrophysics%20-%20A&A&rft.date=2024&rft.volume=681&rft.spage=L19&rft.epage=L19&rft.eissn=0004-6361&rft.issn=0004-6361&rft.au=BOP,%20Cheikh%20T.&AG%C3%9ANDEZ,%20Marcelino&CERNICHARO,%20Jose&LEFLOCH,%20Bertrand&LIQUE,%20Fran%C3%A7ois&rft.genre=article


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