Protostars -- Oral Presentation

X-rays from protostars

Thierry Montmerle, Laboratoire d'Astrophysique de Grenoble (France)

X-ray emission from young stars is most generally a proxy for their magnetic activity. In some cases, the X-rays come from magnetically channeled accretion shocks onto the stars, or from shocks between bipolar jets and the surrounding molecular clouds. In protostars, the X-ray emission may be more closely linked with magnetic interactions between the central, growing stars and their accretion disks, which play a central role in the accretion-ejection mechanism. The stage at which X-rays appear, which may regulate the coupling between the protostellar envelope and the magnetic fields, is however still debated. I will emphasize the importance of a multi-wavelength (X-IR-mm) approach to understand the evolution of protostars.