Séminaire IPAG

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How to spin down a classical T Tauri star?

jeudi 5 mai 2022 - 11h00

George Pantolmos - IPAG
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Classical T Tauri stars (CTTs) magnetically interact with their surrounding disks, a process that controls their rotational evolution. Observations show that CTTs maintain a constant rotation in time, indicative of angular-momentum-loss processes that prevent their stellar spin rates from increasing, due to both accretion and contraction. In this talk, I will present MHD numerical simulations, which attempt to describe the mechanisms governing the angular-momentum transport in star-disk systems. Outflows such as magnetized stellar winds and magnetospheric ejections have been proposed to explain the observed slow rotation of CTTs. I will demonstrate that stellar winds originated from CTTs brake the stellar rotation more efficiently than outflows from diskless stars. However, these winds should eject at >10% of the mass-accretion rate in order to counteract the stellar spin-up due to accretion. According to previous numerical studies of star-disk interaction (SDI), accretion in CTTs occurs in two different states: stable or unstable. I will show that, a stellar spin-down/-equilibrium requires the presence of stable accretion. Finally, I will discuss the contribution of the two processes arising from SDI (ie, accretion and magnetospheric ejections) to such spin-down stellar torques.

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Hôtes : Benoît Cerutti

Salle Manuel Forestini, 414 rue de la piscine, 38400 Saint Martin d'Hères