Request for expert advice on Sci Fi story premise

I'd like some opinion on the following sci fi story plot premise. In the
story a nearby supanova is going to have a catastrophic effect on the
earth's atmosphere. I am considering that a type Ia supernova could occur
in almost any random star within about 30LY and cause very nasty gamma ray
and x-ray radiation to bombard the atmosphere. Is it feasible that there
could be an undetected white dwarf companion star to one of the stars within
this sort of range? I've read scientific papers that suggest there could be
quite a lot of undetected white dwarfs out there.

Rich Woods