(Sub)millimeter emission lines of molecules in born-Again stars?

Context. Born-Again stars provide a unique possibility to study the evolution of the circumstellar envelope of evolved stars in human timescales. Up until now, most of the observations of the circumstellar material in these stars have been limited to studying the relatively hot gas and dust. In othe...

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Autores: Tafoya, D., Toalá, Jesús A., Vlemmings, W. H. T., Guerrero, Martín A., Beck, E. D., González, M., Kimeswenger, S., Zijlstra, Albert, Sánchez-Monge, Á., Treviño-Morales, S. P.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2017
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/167600
Acceso en línea:http://hdl.handle.net/10261/167600
Access Level:acceso abierto
Palabra clave:Circumstellar matter
Stars: mass-loss
Planetary nebulae: general
Stars: AGB & post-AGB
Stars: carbon
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spelling (Sub)millimeter emission lines of molecules in born-Again stars?Tafoya, D.Toalá, Jesús A.Vlemmings, W. H. T.Guerrero, Martín A.Beck, E. D.González, M.Kimeswenger, S.Zijlstra, AlbertSánchez-Monge, Á.Treviño-Morales, S. P.Circumstellar matterStars: mass-lossPlanetary nebulae: generalStars: AGB & post-AGBStars: carbonContext. Born-Again stars provide a unique possibility to study the evolution of the circumstellar envelope of evolved stars in human timescales. Up until now, most of the observations of the circumstellar material in these stars have been limited to studying the relatively hot gas and dust. In other evolved stars, the emission from rotational transitions of molecules, such as CO, is commonly used to study the cool component of their circumstellar envelopes. Thus, the detection and study of molecular gas in born-Again stars is of great importance when attempting to understand their composition and chemical evolution. In addition, the molecular emission is an invaluable tool for exploring the physical conditions, kinematics, and formation of asymmetric structures in the circumstellar envelopes of these evolved stars. However, up until now, all attempts to detect molecular emission from the cool material around born-Again stars have failed. Aims. We searched for emission from rotational transitions of molecules in the hydrogen-deficient circumstellar envelopes of bornagain stars to explore the chemical composition, kinematics, and physical parameters of the relatively cool gas. Methods. We carried out observations using the APEX and IRAM 30 m telescopes to search for molecular emission toward four well-studied born-Again stars, V4334 Sgr, V605 Aql, A30, and A78, that are thought to represent an evolutionary sequence. Results. For the first time, we detected emission from HCN and HCN molecules toward V4334 Sgr, and CO emission in V605 Aql. No molecular emission was detected above the noise level toward A30 and A78. The detected lines exhibit broad linewidths 150 km s, which indicates that the emission comes from gas ejected during the born-Again event, rather than from the old planetary nebula. A first estimate of the HCN/HCN abundance ratio in the circumstellar environment of V4334 Sgr is ≈ 3, which is similar to the value of the 12C/13C ratio measured from other observations. We derived a rotational temperature of Trot = 13 ± 1 K, and a total column density of NHCN = 1:6 ± 0:1 × 10 cm for V4334 Sgr. This result sets a lower limit on the amount of hydrogen that was ejected into the wind during the born-Again event of this source. For V605 Aql, we obtained a lower limit for the integrated line intensities I12CO/I13CO > 4.©ESO 2017.D.T. and W.V. acknowledge support from ERC consolidator grant 614264. A.A.Z. acknowledges funding from the UK STFC research council. A. S.-M. thanks the Deutsche Forschungsgemeinschaft (DFG) for funding support via the collaborative research grant SFB 956, project A6. S.P.T.M. thanks the Spanish MINECO for funding support from grants AYA2012-32032, CSD2009-00038, FIS2012-32096, and ERC under ERC-2013-SyG, G. A. 610256 NANOCOSMOSPeer ReviewedEDP SciencesEuropean CommissionScience and Technology Facilities Council (UK)Ministerio de Economía y Competitividad (España)European Research CouncilGerman Research FoundationConsejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]2018201820172018info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Publisher's versioninfo:eu-repo/semantics/publishedVersionhttp://hdl.handle.net/10261/167600reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Inglés#PLACEHOLDER_PARENT_METADATA_VALUE#info:eu-repo/grantAgreement/EC/FP7/610256Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/1676002026-05-22T06:33:51Z
dc.title.none.fl_str_mv (Sub)millimeter emission lines of molecules in born-Again stars?
title (Sub)millimeter emission lines of molecules in born-Again stars?
spellingShingle (Sub)millimeter emission lines of molecules in born-Again stars?
Tafoya, D.
Circumstellar matter
Stars: mass-loss
Planetary nebulae: general
Stars: AGB & post-AGB
Stars: carbon
title_short (Sub)millimeter emission lines of molecules in born-Again stars?
title_full (Sub)millimeter emission lines of molecules in born-Again stars?
title_fullStr (Sub)millimeter emission lines of molecules in born-Again stars?
title_full_unstemmed (Sub)millimeter emission lines of molecules in born-Again stars?
title_sort (Sub)millimeter emission lines of molecules in born-Again stars?
dc.creator.none.fl_str_mv Tafoya, D.
Toalá, Jesús A.
Vlemmings, W. H. T.
Guerrero, Martín A.
Beck, E. D.
González, M.
Kimeswenger, S.
Zijlstra, Albert
Sánchez-Monge, Á.
Treviño-Morales, S. P.
author Tafoya, D.
author_facet Tafoya, D.
Toalá, Jesús A.
Vlemmings, W. H. T.
Guerrero, Martín A.
Beck, E. D.
González, M.
Kimeswenger, S.
Zijlstra, Albert
Sánchez-Monge, Á.
Treviño-Morales, S. P.
author_role author
author2 Toalá, Jesús A.
Vlemmings, W. H. T.
Guerrero, Martín A.
Beck, E. D.
González, M.
Kimeswenger, S.
Zijlstra, Albert
Sánchez-Monge, Á.
Treviño-Morales, S. P.
author2_role author
author
author
author
author
author
author
author
author
dc.contributor.none.fl_str_mv European Commission
Science and Technology Facilities Council (UK)
Ministerio de Economía y Competitividad (España)
European Research Council
German Research Foundation
Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv Circumstellar matter
Stars: mass-loss
Planetary nebulae: general
Stars: AGB & post-AGB
Stars: carbon
topic Circumstellar matter
Stars: mass-loss
Planetary nebulae: general
Stars: AGB & post-AGB
Stars: carbon
description Context. Born-Again stars provide a unique possibility to study the evolution of the circumstellar envelope of evolved stars in human timescales. Up until now, most of the observations of the circumstellar material in these stars have been limited to studying the relatively hot gas and dust. In other evolved stars, the emission from rotational transitions of molecules, such as CO, is commonly used to study the cool component of their circumstellar envelopes. Thus, the detection and study of molecular gas in born-Again stars is of great importance when attempting to understand their composition and chemical evolution. In addition, the molecular emission is an invaluable tool for exploring the physical conditions, kinematics, and formation of asymmetric structures in the circumstellar envelopes of these evolved stars. However, up until now, all attempts to detect molecular emission from the cool material around born-Again stars have failed. Aims. We searched for emission from rotational transitions of molecules in the hydrogen-deficient circumstellar envelopes of bornagain stars to explore the chemical composition, kinematics, and physical parameters of the relatively cool gas. Methods. We carried out observations using the APEX and IRAM 30 m telescopes to search for molecular emission toward four well-studied born-Again stars, V4334 Sgr, V605 Aql, A30, and A78, that are thought to represent an evolutionary sequence. Results. For the first time, we detected emission from HCN and HCN molecules toward V4334 Sgr, and CO emission in V605 Aql. No molecular emission was detected above the noise level toward A30 and A78. The detected lines exhibit broad linewidths 150 km s, which indicates that the emission comes from gas ejected during the born-Again event, rather than from the old planetary nebula. A first estimate of the HCN/HCN abundance ratio in the circumstellar environment of V4334 Sgr is ≈ 3, which is similar to the value of the 12C/13C ratio measured from other observations. We derived a rotational temperature of Trot = 13 ± 1 K, and a total column density of NHCN = 1:6 ± 0:1 × 10 cm for V4334 Sgr. This result sets a lower limit on the amount of hydrogen that was ejected into the wind during the born-Again event of this source. For V605 Aql, we obtained a lower limit for the integrated line intensities I12CO/I13CO > 4.©ESO 2017.
publishDate 2017
dc.date.none.fl_str_mv 2017
2018
2018
2018
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
Publisher's version
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/167600
url http://hdl.handle.net/10261/167600
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv #PLACEHOLDER_PARENT_METADATA_VALUE#
info:eu-repo/grantAgreement/EC/FP7/610256
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv EDP Sciences
publisher.none.fl_str_mv EDP Sciences
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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score 15.811543

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