IALP   13078
INSTITUTO DE ASTROFISICA LA PLATA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Tracing the mass-loss history of B[e] supergiants.
Autor/es:
KRAUS, M.; CIDALE, L.; ARIAS, M. L.; TORRES, A.; ARET, A.; BORGES FERNANDES, M.; MURATORE, M. F.; CURE, M; OKSALA M. E.
Lugar:
Rodas
Reunión:
Congreso; Massive Stars: From Alpha to Omega; 2013
Resumen:
The post-main sequence evolution of massive stars encompasses several phases with strong, often eruptive mass-loss events, including the puzzling B[e] supergiants (B[e]SG). Stars in this group are surrounded by disks which are cool and dense, and give rise to a complex chemistry, producing molecules and dust. The original idea was that these disks have been formed via a steady, but slow, high density equatorially confined wind. However, recent observations revealed that the circumstellar material is located in detached disks or rings, sometimes even multiple rings, favouring a scenario in which mass loss happens episodically rather than smoothly. Furthermore, time-resolved observations of these disk or ring structures implied a high variability in density and kinematics. Some Galactic B[e]SGs were recently found to be in binaries, and in a few cases, the disks are circumbinary instead of circumstellar. We have initiated an observing campaign using high-resolution optical and near-infrared spectroscopy aimed at studying the structure and kinematics of the circumstellar material of B[e]SGs. While in the optical spectral range several forbidden emission lines can be used as ideal tracers for the ionized and neutral atomic disk regions close to the star, near-infrared spectra host band emission from molecules such as CO, which are excellent indicators for the disk conditions at larger distances. Here we present first results and discuss possible mass-loss history scenarios for some of these enigmatic stars.