CP and related phenomena in the context of Stellar Evolution
/ Authors
J. Braithwaite, T. Akgun, E. Alecian, A. Kholtygin, J. Landstreet, S. Mathis, G. Michaud, J. Portnoy, G. Alecian, V. Bychkov
and 17 more authors
L. Bychkova, N. Drake, S. Fabrika, A. Reisenegger, R. Steinitz, M. Cita, U. Bonn, Universidad Cat'olica Santiago, Observatoire de Paris, Saint Petersburg State University, U. W. Ontario, Armagh Observatory, CEA-Saclay, U. Montr'eal, Sami Shamoon College of Engineering, Special Astrophysical Observatory Russia, Ben-Gurion University
/ Abstract
Abstract We review the interaction in intermediate and high mass stars between their evolution and magnetic and chemical properties. We describe the theory of Ap-star ‘fossil’ fields, before touching on the expected secular diffusive processes which give rise to evolution of the field. We then present recent results from a spectropolarimetric survey of Herbig Ae/Be stars, showing that magnetic fields of the kind seen on the main-sequence already exist during the pre-main sequence phase, in agreement with fossil field theory, and that the origin of the slow rotation of Ap/Bp stars also lies early in the pre-main sequence evolution; we also present results confirming a lack of stars with fields below a few hundred gauss. We then seek which macroscopic motions compete with atomic diffusion in determining the surface abundances of AmFm stars. While turbulent transport and mass loss, in competition with atomic diffusion, are both able to explain observed surface abundances, the interior abundance distribution is different enough to potentially lead to a test using asterosismology. Finally we review progress on the turbulence-driving and mixing processes in stellar radiative zones.
Journal: Proceedings of the International Astronomical Union