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Testing grain surface chemistry : a survey of deuterated formaldehyde and methanol in low-mass Class 0 protostars

dc.contributor.authorPARISE, B.
hal.structure.identifierLaboratoire d'Astrophysique de Grenoble [LAOG]
dc.contributor.authorCECCARELLI, C.
dc.contributor.authorTIELENS, A. G. G. M.
hal.structure.identifierLaboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
hal.structure.identifierObservatoire aquitain des sciences de l'univers [OASU]
hal.structure.identifierLaboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
dc.contributor.authorCASTETS, Alain
dc.contributor.authorCAUX, E.
dc.contributor.authorLEFLOCH, B.
dc.contributor.authorMARET, S.
dc.date.created2006
dc.date.issued2006
dc.identifier.issn0004-6361
dc.description.abstractEnContext : Despite the low cosmic abundance of deuterium (D/H ~ 1e-5), large degrees of deuterium fractionation in molecules are observed in star forming regions with enhancements that can reach 13 orders of magnitude, which current models have difficulties to account for. Aims : Multi-isotopologue observations are a very powerful constraint for chemical models. The aim of our observations is to understand the processes forming the observed large abundances of methanol and formaldehyde in low-mass protostellar envelopes (gas-phase processes ? chemistry on the grain surfaces ?) and better constrain the chemical models. Methods : Using the IRAM 30m single-dish telescope, we observed deuterated formaldehyde (HDCO and D2CO) and methanol (CH2DOH, CH3OD, and CHD2OH) towards a sample of seven low-mass class 0 protostars. Using population diagrams, we then derive the fractionation ratios of these species (abundance ratio between the deuterated molecule and its main isotopologue) and compare them to the predictions of grain chemistry models. Results : These protostars show a similar level of deuteration as in IRAS16293-2422, where doubly-deuterated methanol -- and even triply-deuterated methanol -- were first detected. Our observations point to the formation of methanol on the grain surfaces, while formaldehyde formation cannot be fully pined down. While none of the scenarii can be excluded (gas-phase or grain chemistry formation), they both seem to require abstraction reactions to reproduce the observed fractionations.
dc.language.isoen
dc.publisherEDP Sciences
dc.subject.enISM: abundances
dc.subject.enISM: molecules
dc.subject.enStars: formation
dc.title.enTesting grain surface chemistry : a survey of deuterated formaldehyde and methanol in low-mass Class 0 protostars
dc.typeArticle de revue
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]/Cosmologie et astrophysique extra-galactique [astro-ph.CO]
dc.subject.halPlanète et Univers [physics]/Astrophysique [astro-ph]
dc.identifier.arxivastro-ph/0603135
bordeaux.journalAstronomy and Astrophysics - A&A
bordeaux.page949
bordeaux.volume453
bordeaux.peerReviewedoui
hal.identifierhal-00109405
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-00109405v1
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