  We show that recently proposed white dwarf models with masses well in excess
of the Chandrasekhar limit, based on modifying the equation of state by a
super-strong magnetic field in the centre, are very far from equilibrium
because of the neglect of Lorentz forces. An upper bound on the central
magnetic fields, from a spherically averaged hydrostatic equation, is much
smaller than the values assumed. Robust estimates of the Lorentz forces are
also made without assuming spherical averaging. These again bear out the
results obtained from a spherically averaged model. In our assessment, these
estimates rule out the possibility that magnetic tension could change the
situation in favor of larger magnetic fields. We conclude that such
super-Chandrasekhar models are unphysical and exploration of their
astrophysical consequences is premature.
  Erratum : We correct certain numerical estimates made in our paper. This
correction however does not alter the conclusion that when Lorentz forces are
taken into account the super-massive white dwarf models, obtained simply by
modifying the equation of state in presence of a super-strong magnetic field in
the centre, fail to be in equilibrium.
