K- and L- band spectroscopy of Be stars

We describe the behaviour of IR hydrogen emission lines of a sample of Be stars and discuss the physical properties of the circumstellar envelopes of Be stars classified in Groups I and II (Mennickent et al. 2009). We find that while Humphreys and Pfund lines of Group I stars form in an optically th...

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Autores principales: Granada, Anahí, Arias, María Laura, Cidale, Lydia Sonia, Mennickent, Ronald E.
Formato: Articulo Comunicacion
Lenguaje:Inglés
Publicado: 2011
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Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/84051
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Sumario:We describe the behaviour of IR hydrogen emission lines of a sample of Be stars and discuss the physical properties of the circumstellar envelopes of Be stars classified in Groups I and II (Mennickent et al. 2009). We find that while Humphreys and Pfund lines of Group I stars form in an optically thick envelope/disk, Group II stars show Pfund lines that form in an optically thick medium and Humphreys lines originating in optically thinner regions. The transition between Groups I and II could be understood in terms of the evolution of the circumstellar disk of the star and might bring clues on the mechanism originating the Be phenomenon.