Speaker
Description
Among 10% of intermediate mass stars, particularly the group of chemically peculiar Ap/Bp-type stars, have very strong magnetic fields of order 1 kGauss or even above. As the stars are radiative,, the magnetic fields are difficult to explain via a dynamo, but are often considered to possible have an origin of fossil fields from the interstellar medium. In this talk, we assess this possibility, considering the available magnetic fields in the interstellar medium and their evolution during gravitational collapse. A crucial phase concerns then the protostellar evolution, which may be convective or radiative depending on the accretion rate of the protostars. We will show that it is very difficult for magnetic fields to survive in the convective phase, but more likely in the radiative one, and will show some representative cases for the possible protostellar evolution. We suggest that at least in some cases, suitable protostellar evolution histories can be obtained to explain the origin of magnetic fields in Ap/Bp-type stars.
