Mass-Radius Relation of Strongly Magnetized White Dwarfs

摘要

Wc study the strongly magnetized white dwarf configurations in a selfconsistent manner as a progenitor of the over-luminous type-la supernovae. We compute static equilibria of white dwarf stars containing a strong magnetic field and present the modification of the white dwarf mass-radius relation caused by the magnetic field. From a static equilibrium study, we find that a maximum white dwarf mass of about 1.9 M_⊙ may be supported if the interior poloidal field is as strong as approximately 10~(10) T. On the other hand if the field is purely toroidal the maximum mass can be more than 5 M_⊙. All these modifications are mainly from the presence of the Lorenz force. The effects of i) modification of the equation of state due to Landau quantization, ii) electrostatic interaction due to ions, iii) general relativistic calculation on the stellar structure and, iv) field geometry are also considered. These strongly magnetised configurations are sensitive to magnetic instabilities where the perturbations grow at the corresponding Alfven time scales.