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SÉMINAIRE DU LERMA
OBSERVATOIRE DE PARIS
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Vendredi 30 avril 2004 à 14 h


77 avenue Denfert Rochereau, Paris 14



Salle de l'Atelier, Observatoire de Paris





What Drives Star Formation?



Richard M. CRUTCHER

(University of Illinois)



Résumé : There are currently two extreme-case theoretical paradigms for what drives star formation: (1) magnetic support of molecular clouds against gravity with ambipolar diffusion leading to core collapse, and (2) compressible turbulence in the interstellar medium that sometimes produces self-gravitating cores, which then collapse once turbulent support dissipates. The fundamental difference between these paradigms is the role of magnetic fields. I will describe specifically how observations of magnetic field strengths and morphologies allow tests of these paradigms, briefly review observational polarization techniques for studying magnetic fields in star formation regions, and describe recent observational results. The recent and previous results of observations of magnetic fields in molecular clouds will then be used to apply the tests, and the results for our understanding of the star formation process will be described.