Torsten Boehm (CNRS - Université de Toulouse)

Rotation, activity and stellar oscillations in Vega? - Illustrating the power of high resolution stellar spectroscopy and velocimetry
Wann Am 23.05.2014 von 10:30 bis 12:00
  • Kolloquium
Wo SH, Hörsaal
Termin übernehmen vCal / iCal

In a first part of my presentation I will show the power of asteroseismology based on high resolution spectroscopy, illustrated on quasi continuous spectroscopic time series of oscillating Herbig Ae stars. Some of these stars are pre-main sequence delta-Scuti pulsators and their strongly irregular frequency spectrum can only be understood by analyzing extensive spectrocopic data sets, enabling the determination of oscillation modes, fundamental stellar parameters as well as the dynamic behaviour of stellar activity tracers (eg. rotational modulation). In a second part  will present velocimetric results at the m/s precision:  the rapidly rotating standard Ae star Vega has been observed during 5 nights with the highly stabilized velocimeter/spectrograph Sophie at OHP/ France. New insights on stellar oscillations in that category of stars have been searched for and are presented. The detailed study of photospheric line variations enabled us to conclude on the stellar rotation period, providing a direct answer to a longlasting polemics between spectroscopists and interferometrists.  I will finish the talk with a short presentation of the challenging Neo-Narval instrumental project, the radial veloicty stabilisation of the Narval/TBL spectropolarimeter.