Séminaire IPAG

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Post-dynamical inspiral phase of common envelope evolution of binaries

jeudi 23 novembre 2023 - 11h00

Damien Gagnier - Institut de Physique Théorique de Prague
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Common envelope evolution is arguably the most crucial major process in binary star evolution, but also the least-well-constrained and more generally one of the most important unsolved challenge in stellar evolution. Despite being numerically challenging and subject to major uncertainties, 3D-hydrodynamic simulations have provided a comprehensive understanding of the dynamical inspiral of the secondary star. However, because of the wide range of temporal and spatial scales that need to be resolved and the associated high numerical cost, such simulations are often halted soon after the end of the dynamical inspiral phase. One thus has to revert to 1D models to simulate the entire common envelope evolution, and suffer their associated limitations. In this presentation, I will present results from the first 3D-(magneto)hydrodynamic simulations focusing on the post-dynamical inspiral phase by means of an original setup mimicking the preceding rapid inspiral, making use of the Athena++ code to solve the (magneto)hydrodynamics equations in spherical coordinates. I will discuss the impact of mass and angular momentum accretion on the orbital contraction timescale of the binary, the short-term variability of mass and angular momentum accretion and its remarkable similarity with that in circumbinary disks, and angular momentum transport within the shared envelope. Finally, I will discuss the mechanisms behind magnetic energy amplification during the post-dynamical inspiral phase of common envelope evolution, and the impact of magnetic fields on binary separation evolution and envelope dynamics.

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Hôtes : Gaylor Wafflard

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