  We present simulations of thermonuclear supernovae admixed with an extended
component of fermionic cold dark matter. We consider the explosion of a
Chandrasekhar-mass white dwarf using the deflagration model with
deflagration-detonation transition with spherical symmetry. The dark matter
component is comparable in size with that of the normal matter, and so the
system is described by two-fluid, one-dimensional Eulerian hydrodynamics. The
explosion leaves all the dark matter trapped as a remnant compact dark star in
all of our considered models. The presence of dark matter lengthens the
deflagration phase to produce more thermo-neutrinos and similar amounts of
iron-group elements compared to those of ordinary explosions with no dark
matter admixture. The dark matter admixed models produce dimmer and broader
light curves, which challenge the role of thermonuclear supernovae as standard
candles in cosmic distance measurement. Our results also suggest a formation
path of dark compact objects which mimic sub-solar-mass black holes as dark
gravitational sources, through near-solar-mass dark matter admixed
thermonuclear supernovae.
