Abstract

This project will allow to unify previously separate efforts in Germany and in Chile to understand the evolution of magnetic fields of massive stars from their birth to their final stage as compact remnants (white dwarfs or neutron stars). Its proponents are experts on stellar evolution, astrophysical magneto-hydrodynamics, space plasmas, and compact objects. In the main stages in which these magnetic fields can be observed (main sequence, white dwarf, and neutron star), they are persistent over the time scales covered so far by observations and organized on large scales, which appears to be consistent with the fact that much or all of these stars is stably stratified, thus not convective, and does not support a large-scale dynamo. Some of the key issues to be addressed in this project are: 1) What is the origin of this magnetic field? Why are a small fraction of massive stars strongly magnetized, whereas most are essentially non-magnetic? 2) What kind of stable magnetic configurations can exist in these stars? What are the conditions for their stability? Does stable stratification play a crucial role? 3) How do these magnetic fields affect the evolution of these stars and particularly their (differential or global) rotation? 4) How does the magnetic field change along the stellar evolution? Is flux-freezing a good approximation? Do dynamo processes play an important role, for instance, in a newborn neutron star? 5) How does the magnetic field evolve in a mature neutron star? Can its decay be the source that powers “magnetars”? These questions will be addressed by combining an analysis of existing observational data, rigorous physical reasoning, analytical calculations, and well-focused numerical computations. The main items to be funded will be a joint postdoc spending half of her or his time in Germany and half in Chile, students, a meeting of all participants in Chile, and travel by participants in both directions.