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Étude des processus physiques de la formation d'étoiles par effondrement gravo-turbulent

Abstract : The angular momentum regulation is a hot topic in star formation. From the molecular cloud to th final star, the system loses most of its angular momentum, and several processes are proposed to explain this phenomenon. We focus on non-ideal magnetohydrodynamics (MHD), which describes the coupling between a fluid and its magnetic field. Its efficiency to regulate the angular momentum in realistic conditions has been shown in several studies. First, we develop a code that computes the chemical equilibrium of elements present in the early stages of star formation. We can therefore obtain the values of coefficients defining the strength of the phyical processes associated with non-ideal MHD. We then take interest in one of them, the Hall effect, still poorly studied in this context. We implement it in the eulerian code RAMSES, and use it to quantify its influence during a gravitational collapse. As predicted by theory, the Hall effect greatly influences the size of the protoplanetary disk, in which planets form, and creates envelopes of gas rotating backward compared to the rest of the system
Keywords : Disk Star
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Submitted on : Monday, January 8, 2018 - 5:09:07 PM
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  • HAL Id : tel-01677949, version 1



Pierre Marchand. Étude des processus physiques de la formation d'étoiles par effondrement gravo-turbulent. Astrophysique [astro-ph]. Université de Lyon, 2017. Français. ⟨NNT : 2017LYSE1154⟩. ⟨tel-01677949⟩



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