Rotation in white dwarfs: stellar evolution models

Abstract

We perform stellar evolution calculations for stars in the mass range 1 . . . 3M⊙, including the physics of rotation, from the zero age main sequence into the TP-AGB stage. We calculate two sets of model sequences, with and without inclusion of magnetic fields. From the final computed models, we can accurately predict the angular momenta and rotational velocities of the emerging white dwarf for each sequence. While sequences including magnetic fields predict white dwarf rotational velocities between 2 and 10 kms−1, those from the non-magnetic sequences are found to be one to two orders of magnitude larger, well above the spectroscopic upper limit derived by Berger et al. (2005). We find the situation analogous to that in the neutron star progenitor mass range, and conclude that internal magnetic fields appear capable to reproduce the observed slow rotation of compact stellar remnants.