Seminar at the IAC by the Advanced Severo Ochoa Fellow S. Simón

The Advanced Severo Ochoa Fellow Sergio Simón Díaz, will give a regular seminar on 2014 April 29th entitled Rotational velocities in Galactic OB stars: the Fourier transform revolution.

Start date: 29 Apr, 2014 - 12:30
End date: 29 Apr, 2014 - 14:00
Location: Aula, IAC Headquarters, Tenerife.
Organizer: Instituto de Astrofísica de Canarias

Abstract:

The application of the Fourier transform (FT) technique to high resolution spectra of OB-type stars has challenged our previous knowledge about stellar rotation in stars in the upper region of the HRD. The FT is an old and powerful tool that has being widely used in the case of cool stars, but only very recently applied to massive stars in a systematic way. In this talk I will present the results of the line-broadening characterization of ~250 Galactic OB-type stars (including dwarfs, giants and supergiants with spectral types O4-B9) from the IACOB spectroscopic database. I will show how these analyses have led to a downward revision of previously determined projected rotational velocities in these stars, and have definitely confirmed the presence of a non-negligible extra line-broadening contribution (commonly called macroturbulent broadening) in the whole OB star domain. I will also provide some notes about the importance of these findings on the evolution of massive stars and the detection of stellar oscillations along the lifetime of these important astrophysical objects.

The research activity of Dr. Simón Díaz is focused around the study of the physical properties of massive stars in the Milky Way and the Magellanic Clouds, also establishing synergies with the study of HII regions and stellar oscillations. He is currently leading the IACOB project and a member of the VLT-FLAMES Tarantula survey collaboration.