Diagnosis of stellar winds and temperature structures in Be stars through the analysis of Mg II lines

We compute non-LTE Mg II line profiles for Be stars by considering 12 energy-level atoms and supposing that the circumstellar medium can be described by an expanding, spherically symmetric flow in which we assume the presence of a chromosphere. The line radiative transfer equation was solved rigorou...

Descripción completa

Detalles Bibliográficos
Autor: Cidale, Lydia Sonia
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:1998
País:Argentina
Institución:Universidad Nacional de La Plata
Repositorio:SEDICI (UNLP)
Idioma:inglés
OAI Identifier:oai:sedici.unlp.edu.ar:10915/2087
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/2087
Access Level:acceso abierto
Palabra clave:Ciencias Astronómicas
estrellas
circumstellar matter; radiative transfer; emission line; Be stars; mass loss
astrofísica
Descripción
Sumario:We compute non-LTE Mg II line profiles for Be stars by considering 12 energy-level atoms and supposing that the circumstellar medium can be described by an expanding, spherically symmetric flow in which we assume the presence of a chromosphere. The line radiative transfer equation was solved rigorously in spherical coordinates and in the comoving frame. The Mg II line profiles predicted by this model coincide with those observed in some Be stars. The calculation was performed for a range of effective temperatures representative of the B spectral type. We have also analyzed the influence on the line profiles of different temperature and velocity distributions in the circumstellar material. The line spectrum variability of a Be star is interpreted as the result of a variable outward mass flux.