The mass limit of white dwarfs with strong magnetic fields in general relativity

Recently, U. Das and B. Mukhopadhyay proposed that the Chandrasekhar limit of a white dwarf could reach a new high level (2.58 M_⊙) if a superstrong magnetic field were considered (Das U and Mukhopadhyay B 2013 Phys. Rev. Lett. 110 071102), where the structure of the strongly magnetized white dwarf (SMWD) is calculated in the framework of Newtonian theory (NT). As the SMWD has a far smaller size, in contrast with the usual expectation, we found that there is an obvious general relativistic effect (GRE) in the SMWD. For example, for the SMWD with a one Landau level system, the super-Chandrasekhar mass limit in general relativity (GR) is approximately 16.5% lower than that in NT. More interestingly, the maximal mass of the white dwarf will be first increased when the magnetic field strength keeps on increasing and reaches the maximal value M=2.48 M_⊙ with B_D=391.5. Then if we further increase the magnetic fields, surprisingly, the maximal mass of the white dwarf will decrease when one takes the GRE into account.