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Séminaire MHD (SEMHD)

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Influence of turbulence and magnetic field on the star-formation process: A theoretical review
Ralf Klessen (Heidelberg)

3 avril 2009

Stars form by gravoturbulent fragmentation of interstellar gas clouds. The supersonic turbulence ubiquitously observed in Galactic molecular gas generates strong density fluctuations with gravity taking over in the densest and most massive regions. Collapse sets in to build up stars and star clusters.
Turbulence plays a dual role. On global scales it provides support, while at the same time it can promote local collapse. Stellar birth is thus intimately linked to the dynamical behavior of parental gas cloud, which governs when and where protostellar cores form, and how they contract and grow in mass via accretion from the surrounding cloud material to build up stars. The thermodynamic behavior of the star forming gas plays a crucial part in fragmentation and influences the stellar mass function as well as the dynamic properties of the nascent stellar cluster.
I will discuss our current understanding of molecular cloud formation in the disk of our Milky Way. In particular, I will focus on the characteristics of interstellar turbulence and on the effects of magnetic fields in star formation.
Bibliographie :
• Reviews on Star Formation:
– Ballesteros-Paredes et al., in Protostars and Planets V, 2007, p. 63.
– Mac Low & Klessen, Reviews of Modern Physics, 76 (2004), 125.
– McKee & Ostriker, Annual Reviews Astronomy & Astrophysics, 45 (2007), 565.
• Molecular Formation/Characteristics of Supersonic Turbulence:
– Dobbs et al., MNRAS, 389 (2008), 1097.
– Federrath, Klessen, Schmidt, Astrophys. J., 692 (2009), 364.
– Jappsen et al., Astron. Astrophys., 345 (2005), 611.

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Non disponible Ralf Klessen (Heidelberg)
Ralf Klessen est professeur (et "managing director") à l’Institut für Theoretische Astrophysik de l’université de Heidelberg (Zentrum für Astronomie).