Hot Molecular Cores and the Formation of Massive Stars

It has been proposed that some hot molecular cores (HMCs) harbor a young embedded massive star, which heats an infalling envelope and accretes mass at a rate high enough to ``choke off'' an incipient H II region. This class of HMCs would mark the youngest phase known of massive star format...

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Authors: Osorio, Mayra, Lizano, Susana, D'Alessio, Paola
Format: article
Status:Versión aceptada para publicación
Publication Date:1999
Country:España
Institution:Consejo Superior de Investigaciones Científicas (CSIC)
Repository:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/378992
Online Access:http://hdl.handle.net/10261/378992
Access Level:Open access
Keyword:H II regions
ISM : clouds
Radiative transfer
Stars : early-type
Stars : formation
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spelling Hot Molecular Cores and the Formation of Massive StarsOsorio, MayraLizano, SusanaD'Alessio, PaolaH II regionsISM : cloudsRadiative transferStars : early-typeStars : formationIt has been proposed that some hot molecular cores (HMCs) harbor a young embedded massive star, which heats an infalling envelope and accretes mass at a rate high enough to ``choke off'' an incipient H II region. This class of HMCs would mark the youngest phase known of massive star formation. In order to test this hypothesis, we model this type of object calculating the radiative transfer through a spherically symmetric dusty envelope infalling onto a central OB star, with accretion rates from Ṁ=6×10-4 to 10-3 Msolar yr-1. The dust thermal spectrum from infrared to radio wavelengths is derived and is compared with the observed fluxes of several hot cores which may be internally heated. We find that the data are best fitted using an envelope with the density distribution resulting from the collapse of a singular logatropic sphere, instead of that of a singular isothermal sphere. We conclude that several of these sources may be undergoing an intense accretion phase and find in all the cases that the accretion luminosity exceeds the stellar luminosity. We discuss the implications of this phase on the formation of massive stars. © 1999. The American Astronomical SocietyWe are greatly indebted with Javier Ballesteros, Mar• a Eugenia Contreras, and Rosa Izela with whom D• az-Miller we originally discussed the work presented here. We also thank Guillem Anglada, Riccardo Cesaroni, Guido Garay, William Henney, Stan Kurtz, Sergio Molinari, Luis F. Rodr• guez, Leonardo Testi, Malcom Walmsley, and Alan Watson for useful discussions and helpful suggestions. We thank Leonardo Testi for providing us the original data for IRAS 23385]6053. Thanks too to Robert Estalella for providing a program to convolve our results with the observing beam. M. O., S. L., and P. D. acknowledge support from DGAPA/UNAM and CONACYT. S. L. also acknowledges support from the Simon Guggenheim Memorial Foundation. M. O. also acknowledges partial support from the Programa de con Cooperacio n Cient• Ðca Iberoame rica (Spain)Peer reviewedAmerican Astronomical SocietyUniversidad Nacional Autónoma de MéxicoConsejo Nacional de Ciencia y Tecnología (México)Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]202520251999info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Postprintinfo:eu-repo/semantics/acceptedVersionhttp://hdl.handle.net/10261/378992reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Ingléshttp://dx.doi.org/10.1086/307929Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/3789922026-05-22T06:33:51Z
dc.title.none.fl_str_mv Hot Molecular Cores and the Formation of Massive Stars
title Hot Molecular Cores and the Formation of Massive Stars
spellingShingle Hot Molecular Cores and the Formation of Massive Stars
Osorio, Mayra
H II regions
ISM : clouds
Radiative transfer
Stars : early-type
Stars : formation
title_short Hot Molecular Cores and the Formation of Massive Stars
title_full Hot Molecular Cores and the Formation of Massive Stars
title_fullStr Hot Molecular Cores and the Formation of Massive Stars
title_full_unstemmed Hot Molecular Cores and the Formation of Massive Stars
title_sort Hot Molecular Cores and the Formation of Massive Stars
dc.creator.none.fl_str_mv Osorio, Mayra
Lizano, Susana
D'Alessio, Paola
author Osorio, Mayra
author_facet Osorio, Mayra
Lizano, Susana
D'Alessio, Paola
author_role author
author2 Lizano, Susana
D'Alessio, Paola
author2_role author
author
dc.contributor.none.fl_str_mv Universidad Nacional Autónoma de México
Consejo Nacional de Ciencia y Tecnología (México)
Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv H II regions
ISM : clouds
Radiative transfer
Stars : early-type
Stars : formation
topic H II regions
ISM : clouds
Radiative transfer
Stars : early-type
Stars : formation
description It has been proposed that some hot molecular cores (HMCs) harbor a young embedded massive star, which heats an infalling envelope and accretes mass at a rate high enough to ``choke off'' an incipient H II region. This class of HMCs would mark the youngest phase known of massive star formation. In order to test this hypothesis, we model this type of object calculating the radiative transfer through a spherically symmetric dusty envelope infalling onto a central OB star, with accretion rates from Ṁ=6×10-4 to 10-3 Msolar yr-1. The dust thermal spectrum from infrared to radio wavelengths is derived and is compared with the observed fluxes of several hot cores which may be internally heated. We find that the data are best fitted using an envelope with the density distribution resulting from the collapse of a singular logatropic sphere, instead of that of a singular isothermal sphere. We conclude that several of these sources may be undergoing an intense accretion phase and find in all the cases that the accretion luminosity exceeds the stellar luminosity. We discuss the implications of this phase on the formation of massive stars. © 1999. The American Astronomical Society
publishDate 1999
dc.date.none.fl_str_mv 1999
2025
2025
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/10261/378992
url http://hdl.handle.net/10261/378992
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv http://dx.doi.org/10.1086/307929
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv American Astronomical Society
publisher.none.fl_str_mv American Astronomical Society
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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