Common envelope simulations and (separately) exploring a new mean-field dynamo effect
University of Rochester
Part 1: Common envelope evolution happens when an evolved star engulfs a companion, leading to a rapid inspiral between the companion and core of the giant star. If enough energy is transferred to the gaseous envelope during this process then it will be ejected, resulting in a binary with a very small separation. I will present the first results from hydrodynamical adaptive mesh refinement simulations of common envelope evolution using the code Astrobear. Part 2: Galaxies and stars like the sun are known to have magnetic fields that are coherent up to scales as large as the system size. But there is also significant magnetic energy on the smaller scales of turbulence. This small-scale component may be strong when the large-scale component is weak and still growing, yet the possible influence of the former on the latter is still largely unexplored. I will argue that in galaxies such small-scale magnetic fluctuations can weaken, and even provide a novel saturation mechanism for, the large-scale dynamo.
Date: Jeudi, le 30 novembre 2017 Heure: 11:30 Lieu: Université de Montréal Pavillon Roger-Gaudry, Local D-460 Contact: Paul Charbonneau