K- and L- band spectroscopy of Be stars

GRANADA, ANAHÍ; ARIAS, MARÍA LAURA; CIDALE, LYDIA; MENNICKENT RONALD

Paris

Simposio; Active OB stars: structure, evolution, mass loss and critical limits; 2010

IAU

We describe the behaviour of IR hydrogen emission lines of a sample of Be stars anddiscuss the physical properties of the circumstellar envelopes of Be stars classified in Groups I andII (Mennickent et al. 2009). We find that while Humphreys and Pfund lines of Group I stars formin an optically thick envelope/disk, Group II stars show Pfund lines that form in an opticallythick medium and Humphreys lines originating in optically thinner regions. The transitionbetween Groups I and II could be understood in terms of the evolution of the circumstellardisk of the star and might bring clues on the mechanism originating the Be phenomenon.