Abstract

Invited Talk - Splinter MassiveStars

Thursday, 10 September 2026, 14:55   (MW-1050)

Magnetic field amplification in stellar mergers and common envelope events

Marco Vetter, Fabian Schneider, Friedrich Röpke, Sebastian Ohlmann, Rüdiger Pakmor, Damien Gagnier, Mike Lau et al.
University Heidelberg, ARI/ZAH and HITS

Binary interactions such as stellar mergers and common-envelope evolution generate strong shear flows within the envelope that amplify magnetic fields by several orders of magnitude, leaving a characteristic imprint on the post-dynamical system. In this talk, I will discuss the mechanisms responsible for magnetic energy amplification and their implications for these interactions, based on three-dimensional magnetohydrodynamic simulations performed with the moving-mesh code AREPO. Particular emphasis will be placed on the amplification processes and the formation of fast, magnetically driven bipolar outflows. These outflows efficiently remove both mass and angular momentum, thereby influencing the subsequent evolution of the system. Taken together, these results demonstrate that magnetic fields play a profound role in these interactions, with important consequences for their evolution and a range of potential observational signatures. These include the formation of magnetic OBA stars and their highly magnetized compact remnants—magnetars and polars—as well as the shaping of asymmetric planetary nebulae.