Study of CS, SiO, and SiS abundances in carbon star envelopes: assessing their role as gas-phase precursors of dust

19 pags., 11 figs., 8 tabs.

Detalhes bibliográficos
Autores: Massalkhi, S., Agúndez, Marcelino, Cernicharo, José
Tipo de documento: artigo
Estado:Versión aceptada para publicación
Data de publicação:2019
País:España
Recursos:Consejo Superior de Investigaciones Científicas (CSIC)
Repositório:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/204154
Acesso em linha:http://hdl.handle.net/10261/204154
Access Level:Acceso aberto
Palavra-chave:Astrochemistry
Molecular processes
Stars: abundances
Stars: AGB and post-AGB
Circumstellar matter
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spelling Study of CS, SiO, and SiS abundances in carbon star envelopes: assessing their role as gas-phase precursors of dustMassalkhi, S.Agúndez, MarcelinoCernicharo, JoséAstrochemistryMolecular processesStars: abundancesStars: AGB and post-AGBCircumstellar matter19 pags., 11 figs., 8 tabs.Aims. We aim to determine the abundances of CS, SiO, and SiS in a large sample of carbon star envelopes covering a wide range of mass loss rates to investigate the potential role that these molecules could play in the formation of dust in the surroundings of the central AGB star. Methods. We surveyed a sample of 25 carbon-rich AGB stars in the λ 2 mm band, more concretely in the J = 3 − 2 line of CS and SiO, and in the J = 7 − 6 and J = 8 − 7 lines of SiS, using the IRAM 30 m telescope. We performed excitation and radiative transfer calculations based on the large velocity gradient (LVG) method to model the observed lines of the molecules and to derive their fractional abundances in the observed envelopes. We also assessed the effect of infrared pumping in the excitation of the molecules.Results. We detected CS in all 25 targeted envelopes, SiO in 24 of them, and SiS in 17 sources. Remarkably, SiS is not detected in any envelope with a mass loss rate below 10−6 M yr−1 while it is detected in all envelopes with mass loss rates above that threshold. We found that CS and SiS have similar abundances in carbon star envelopes, while SiO is present with a lower abundance. We also found a strong correlation in which the denser the envelope, the less abundant are CS and SiO. The trend is however only tentatively seen for SiS in the range of high mass loss rates. Furthermore, we found a relation in which the integrated flux of the MgS dust feature at 30 µm increases as the fractional abundance of CS decreases. Conclusions. The decline in the fractional abundance of CS with increasing density could be due to gas-phase chemistry in the inner envelope or to adsorption onto dust grains. The latter possibility is favored by a correlation between the CS fractional abundance and the 30 µm feature, which suggests that CS is efficiently incorporated onto MgS dust around C-rich AGB stars. In the case of SiO, the observed abundance depletion with increasing density is most likely caused by an efficient incorporation onto dust grains. We conclude that CS, SiO (very likely), and SiS (tentatively) are good candidates to act as gas-phase precursors of dust in C-rich AGB envelopes.We acknowledge funding support from the European Research Council (ERC Grant 610256: NANOCOSMOS) and from Spanish MINECO through grants AYA2012-32032 and AYA2016-75066-C2-1-P. M.A. thanks Spanish MINECO for funding support through the Ramón y Cajal programme (RyC-2014-16277).Springer NatureEuropean CommissionMinisterio de Economía y Competitividad (España)Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]2020202020192020info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Postprintinfo:eu-repo/semantics/acceptedVersionhttp://hdl.handle.net/10261/204154reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Inglés#PLACEHOLDER_PARENT_METADATA_VALUE##PLACEHOLDER_PARENT_METADATA_VALUE#info:eu-repo/grantAgreement/EC/FP7/610256info:eu-repo/grantAgreement/MINECO/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/AYA2016-75066-C2-1-Phttp://dx.doi.org/10.1051/0004-6361/201935069Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/2041542026-05-22T06:33:51Z
dc.title.none.fl_str_mv Study of CS, SiO, and SiS abundances in carbon star envelopes: assessing their role as gas-phase precursors of dust
title Study of CS, SiO, and SiS abundances in carbon star envelopes: assessing their role as gas-phase precursors of dust
spellingShingle Study of CS, SiO, and SiS abundances in carbon star envelopes: assessing their role as gas-phase precursors of dust
Massalkhi, S.
Astrochemistry
Molecular processes
Stars: abundances
Stars: AGB and post-AGB
Circumstellar matter
title_short Study of CS, SiO, and SiS abundances in carbon star envelopes: assessing their role as gas-phase precursors of dust
title_full Study of CS, SiO, and SiS abundances in carbon star envelopes: assessing their role as gas-phase precursors of dust
title_fullStr Study of CS, SiO, and SiS abundances in carbon star envelopes: assessing their role as gas-phase precursors of dust
title_full_unstemmed Study of CS, SiO, and SiS abundances in carbon star envelopes: assessing their role as gas-phase precursors of dust
title_sort Study of CS, SiO, and SiS abundances in carbon star envelopes: assessing their role as gas-phase precursors of dust
dc.creator.none.fl_str_mv Massalkhi, S.
Agúndez, Marcelino
Cernicharo, José
author Massalkhi, S.
author_facet Massalkhi, S.
Agúndez, Marcelino
Cernicharo, José
author_role author
author2 Agúndez, Marcelino
Cernicharo, José
author2_role author
author
dc.contributor.none.fl_str_mv European Commission
Ministerio de Economía y Competitividad (España)
Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv Astrochemistry
Molecular processes
Stars: abundances
Stars: AGB and post-AGB
Circumstellar matter
topic Astrochemistry
Molecular processes
Stars: abundances
Stars: AGB and post-AGB
Circumstellar matter
description 19 pags., 11 figs., 8 tabs.
publishDate 2019
dc.date.none.fl_str_mv 2019
2020
2020
2020
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
Postprint
info:eu-repo/semantics/acceptedVersion
format article
status_str acceptedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/204154
url http://hdl.handle.net/10261/204154
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv #PLACEHOLDER_PARENT_METADATA_VALUE#
#PLACEHOLDER_PARENT_METADATA_VALUE#
info:eu-repo/grantAgreement/EC/FP7/610256
info:eu-repo/grantAgreement/MINECO/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/AYA2016-75066-C2-1-P
http://dx.doi.org/10.1051/0004-6361/201935069
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv Springer Nature
publisher.none.fl_str_mv Springer Nature
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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