What triggers type Ia supernovae: Prompt detonations from primordial black holes or companion stars?

We set up and perform collision rate simulations between dark matter in the form of asteroid-mass primordial black holes (PBHs) and white dwarf stars. These encounters trigger prompt detonations and could be the key to solving the ignition mystery of type Ia supernovae. Our framework is flexible enough to cover the full range of progenitor white dwarf masses, host galaxy stellar masses, galactocentric radial offsets, and cosmic time. The rate distribution pattern is consistent with exhaustive literature observational determinations for a slightly extended log-normal PBH mass spectrum. Most strikingly, the so far unexplained brightness distribution comes out without finetuning. We find no severe contradictions, except that the inferred PBH mass scale is unpredicted from first principles.