Non-thermal processes in bowshocks of runaway stars: Application to ζ Ophiuchi

Context. Runaway massive stars are O-and B-type stars with high spatial velocities with respect to the interstellar medium. These stars can produce bowshocks in the surrounding gas. Bowshocks develop as arc-shaped structures, with bows pointing to the same direction as the stellar velocity, while th...

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Detalhes bibliográficos
Autores: Valle, María Elena del, Romero, Gustavo Esteban
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2012
País:Argentina
Recursos:Universidad Nacional de La Plata
Repositorio:SEDICI (UNLP)
Idioma:inglés
OAI Identifier:oai:sedici.unlp.edu.ar:10915/84645
Acesso em linha:http://sedici.unlp.edu.ar/handle/10915/84645
Access Level:acceso abierto
Palavra-chave:Ciencias Astronómicas
Gamma rays: general
ISM: jets and outflows
Radiation mechanisms: non-thermal
Stars: early-type
Stars: individual:ζOphiuchi
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spelling Non-thermal processes in bowshocks of runaway stars: Application to ζ OphiuchiValle, María Elena delRomero, Gustavo EstebanCiencias AstronómicasGamma rays: generalISM: jets and outflowsRadiation mechanisms: non-thermalStars: early-typeStars: individual:ζOphiuchiContext. Runaway massive stars are O-and B-type stars with high spatial velocities with respect to the interstellar medium. These stars can produce bowshocks in the surrounding gas. Bowshocks develop as arc-shaped structures, with bows pointing to the same direction as the stellar velocity, while the star moves supersonically through the interstellar gas. The piled-up shocked matter emits thermal radiation and a population of locally accelerated relativistic particles is expected to produce non-thermal emission over a wide range of energies. Aims. We aim to model the non-thermal radiation produced in these sources. Methods. Under some assumptions, we computed the non-thermal emission produced by the relativistic particles and the thermal radiation caused by free-free interactions, for O4I and O9I stars. We applied our model to ζ Oph (HD 149757), an intensively studied massive star seen from the northern hemisphere. This star has spectral type O9.5V and is a well-known runaway. Results. Spectral energy distributions of massive runaways are predicted for the whole electromagnetic spectrum. Conclusions. We conclude that the non-thermal radiation might be detectable at various energy bands for relatively nearby runaway stars, especially at high-energy gamma rays. Inverse Compton scattering with photons from the heated dust gives the most important contribution to the high-energy spectrum. This emission approaches Fermi sensitivities in the case of ζ Oph.Facultad de Ciencias Astronómicas y Geofísicas2012info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfhttp://sedici.unlp.edu.ar/handle/10915/84645enginfo:eu-repo/semantics/altIdentifier/issn/0004-6361info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201218937info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by-nc-sa/4.0/Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2024-05-08T12:54:03Zoai:sedici.unlp.edu.ar:10915/84645Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292024-05-08 12:54:03.266SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv Non-thermal processes in bowshocks of runaway stars: Application to ζ Ophiuchi
title Non-thermal processes in bowshocks of runaway stars: Application to ζ Ophiuchi
spellingShingle Non-thermal processes in bowshocks of runaway stars: Application to ζ Ophiuchi
Valle, María Elena del
Ciencias Astronómicas
Gamma rays: general
ISM: jets and outflows
Radiation mechanisms: non-thermal
Stars: early-type
Stars: individual:ζOphiuchi
title_short Non-thermal processes in bowshocks of runaway stars: Application to ζ Ophiuchi
title_full Non-thermal processes in bowshocks of runaway stars: Application to ζ Ophiuchi
title_fullStr Non-thermal processes in bowshocks of runaway stars: Application to ζ Ophiuchi
title_full_unstemmed Non-thermal processes in bowshocks of runaway stars: Application to ζ Ophiuchi
title_sort Non-thermal processes in bowshocks of runaway stars: Application to ζ Ophiuchi
dc.creator.none.fl_str_mv Valle, María Elena del
Romero, Gustavo Esteban
author Valle, María Elena del
author_facet Valle, María Elena del
Romero, Gustavo Esteban
author_role author
author2 Romero, Gustavo Esteban
author2_role author
dc.subject.none.fl_str_mv Ciencias Astronómicas
Gamma rays: general
ISM: jets and outflows
Radiation mechanisms: non-thermal
Stars: early-type
Stars: individual:ζOphiuchi
topic Ciencias Astronómicas
Gamma rays: general
ISM: jets and outflows
Radiation mechanisms: non-thermal
Stars: early-type
Stars: individual:ζOphiuchi
description Context. Runaway massive stars are O-and B-type stars with high spatial velocities with respect to the interstellar medium. These stars can produce bowshocks in the surrounding gas. Bowshocks develop as arc-shaped structures, with bows pointing to the same direction as the stellar velocity, while the star moves supersonically through the interstellar gas. The piled-up shocked matter emits thermal radiation and a population of locally accelerated relativistic particles is expected to produce non-thermal emission over a wide range of energies. Aims. We aim to model the non-thermal radiation produced in these sources. Methods. Under some assumptions, we computed the non-thermal emission produced by the relativistic particles and the thermal radiation caused by free-free interactions, for O4I and O9I stars. We applied our model to ζ Oph (HD 149757), an intensively studied massive star seen from the northern hemisphere. This star has spectral type O9.5V and is a well-known runaway. Results. Spectral energy distributions of massive runaways are predicted for the whole electromagnetic spectrum. Conclusions. We conclude that the non-thermal radiation might be detectable at various energy bands for relatively nearby runaway stars, especially at high-energy gamma rays. Inverse Compton scattering with photons from the heated dust gives the most important contribution to the high-energy spectrum. This emission approaches Fermi sensitivities in the case of ζ Oph.
publishDate 2012
dc.date.none.fl_str_mv 2012
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
Articulo
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://sedici.unlp.edu.ar/handle/10915/84645
url http://sedici.unlp.edu.ar/handle/10915/84645
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/issn/0004-6361
info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201218937
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
eu_rights_str_mv openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
dc.format.none.fl_str_mv application/pdf
dc.source.none.fl_str_mv reponame:SEDICI (UNLP)
instname:Universidad Nacional de La Plata
instacron:UNLP
instname_str Universidad Nacional de La Plata
instacron_str UNLP
institution UNLP
reponame_str SEDICI (UNLP)
collection SEDICI (UNLP)
repository.name.fl_str_mv SEDICI (UNLP) - Universidad Nacional de La Plata
repository.mail.fl_str_mv alira@sedici.unlp.edu.ar
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score 15,808905

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