Spectro-interferometry study of red supergiants

Red supergiant stars (RSGs) are cool and massive stars that evolve toward Wolf-Rayet stars and supernovae. They have extended atmospheres and strong stellar winds, which lead to significant mass loss. Currently, the mechanisms that explain the large observed atmospheric extensions are open to debate. The estimation of the fundamental parameters of these stars and their location in the HR diagram are very important for calibrating the evolutionary models and understanding how the mass loss affects their evolution.

We have studied a representative sample of RSGs. We used spectro-interferometric observations in near-infrared wavelength with the AMBER instrument of the Very Large Telescope Interferometer (VLTI), located at the Paranal Observatory in Chile. The resolution obtained with this technique is essential to determine the angular diameter of the photosphere of these stars and to observe in detail their atmosphere. Thanks to our observations, we can estimate the fundamental parameters of these stars, locate them in the HR diagram, and study the structure of their extended atmospheres. For this study, we have compared these observations with three theoretical models: a hydrostatic model (PHOENIX), a 3-D convective model, and a 1-D pulsation model. We have also observed a sample of red giant stars to see if these less massive and less evolved stars have extended atmospheres too.

28/01/2016 - 12:30
Dr. Belén Arroyo-Torres
Universidad de Valencia