Modelling chromospheric line profiles in NGC 2808: Evidence of mass loss from RGB stars

In this study we test the possibility that the asymmetry in the profiles of the Hα and Ca II K lines in red giant stars is due to the presence of an active chromosphere rather than to mass loss. To this end, we compare line profiles computed using relevant model chromospheres to profiles of the Hα a...

Descripción completa

Guardado en:
Detalles Bibliográficos
Autores principales: Mauas, P.J.D., Cacciari, C., Pasquini, L.
Formato: JOUR
Materias:
Globular clusters: individual: NGC 2808
Line: profiles
Stars: atmospheres
Stars: mass loss
Stars: Population II
Techniques: spectroscopic
Astronomy
Computer simulation
Extraterrestrial atmospheres
Spectrum analysis
Galaxies
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00046361_v454_n2_p609_Mauas
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_00046361_v454_n2_p609_Mauas
record_format dspace
spelling todo:paper_00046361_v454_n2_p609_Mauas2023-10-03T14:00:15Z Modelling chromospheric line profiles in NGC 2808: Evidence of mass loss from RGB stars Mauas, P.J.D. Cacciari, C. Pasquini, L. Globular clusters: individual: NGC 2808 Line: profiles Stars: atmospheres Stars: mass loss Stars: Population II Techniques: spectroscopic Astronomy Computer simulation Extraterrestrial atmospheres Spectrum analysis Globular clusters: individual: NGC 2808 Line: profiles Stars: atmospheres Stars: mass loss Stars: Population II Techniques: spectroscopic Galaxies In this study we test the possibility that the asymmetry in the profiles of the Hα and Ca II K lines in red giant stars is due to the presence of an active chromosphere rather than to mass loss. To this end, we compare line profiles computed using relevant model chromospheres to profiles of the Hα and Ca II K lines observed in five red giant stars of the globular cluster NGC 2808. The spectra were taken with FLAMES during the science verification, using the UVES mode at high resolution (R = 43 000) for the Hα line, and GIRAFFE in MEDUSA mode (R = 20 000) for the Ca II K line. We find that the observed profiles are better described if a negative (outward) velocity field is included in the model chromospheres. This leads to mass loss rates of a few 10 -9 M⊙ yr-1, so very close to the requirements of the stellar evolution theory. © ESO 2006. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00046361_v454_n2_p609_Mauas
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Globular clusters: individual: NGC 2808
Line: profiles
Stars: atmospheres
Stars: mass loss
Stars: Population II
Techniques: spectroscopic
Astronomy
Computer simulation
Extraterrestrial atmospheres
Spectrum analysis
Globular clusters: individual: NGC 2808
Line: profiles
Stars: atmospheres
Stars: mass loss
Stars: Population II
Techniques: spectroscopic
Galaxies
spellingShingle Globular clusters: individual: NGC 2808
Line: profiles
Stars: atmospheres
Stars: mass loss
Stars: Population II
Techniques: spectroscopic
Astronomy
Computer simulation
Extraterrestrial atmospheres
Spectrum analysis
Globular clusters: individual: NGC 2808
Line: profiles
Stars: atmospheres
Stars: mass loss
Stars: Population II
Techniques: spectroscopic
Galaxies
Mauas, P.J.D.
Cacciari, C.
Pasquini, L.
Modelling chromospheric line profiles in NGC 2808: Evidence of mass loss from RGB stars
topic_facet Globular clusters: individual: NGC 2808
Line: profiles
Stars: atmospheres
Stars: mass loss
Stars: Population II
Techniques: spectroscopic
Astronomy
Computer simulation
Extraterrestrial atmospheres
Spectrum analysis
Globular clusters: individual: NGC 2808
Line: profiles
Stars: atmospheres
Stars: mass loss
Stars: Population II
Techniques: spectroscopic
Galaxies
description In this study we test the possibility that the asymmetry in the profiles of the Hα and Ca II K lines in red giant stars is due to the presence of an active chromosphere rather than to mass loss. To this end, we compare line profiles computed using relevant model chromospheres to profiles of the Hα and Ca II K lines observed in five red giant stars of the globular cluster NGC 2808. The spectra were taken with FLAMES during the science verification, using the UVES mode at high resolution (R = 43 000) for the Hα line, and GIRAFFE in MEDUSA mode (R = 20 000) for the Ca II K line. We find that the observed profiles are better described if a negative (outward) velocity field is included in the model chromospheres. This leads to mass loss rates of a few 10 -9 M⊙ yr-1, so very close to the requirements of the stellar evolution theory. © ESO 2006.
format JOUR
author Mauas, P.J.D.
Cacciari, C.
Pasquini, L.
author_facet Mauas, P.J.D.
Cacciari, C.
Pasquini, L.
author_sort Mauas, P.J.D.
title Modelling chromospheric line profiles in NGC 2808: Evidence of mass loss from RGB stars
title_short Modelling chromospheric line profiles in NGC 2808: Evidence of mass loss from RGB stars
title_full Modelling chromospheric line profiles in NGC 2808: Evidence of mass loss from RGB stars
title_fullStr Modelling chromospheric line profiles in NGC 2808: Evidence of mass loss from RGB stars
title_full_unstemmed Modelling chromospheric line profiles in NGC 2808: Evidence of mass loss from RGB stars
title_sort modelling chromospheric line profiles in ngc 2808: evidence of mass loss from rgb stars
url http://hdl.handle.net/20.500.12110/paper_00046361_v454_n2_p609_Mauas
work_keys_str_mv AT mauaspjd modellingchromosphericlineprofilesinngc2808evidenceofmasslossfromrgbstars
AT cacciaric modellingchromosphericlineprofilesinngc2808evidenceofmasslossfromrgbstars
AT pasquinil modellingchromosphericlineprofilesinngc2808evidenceofmasslossfromrgbstars
_version_ 1807317890542600192

Ejemplares similares