How do you kill a civilization?

Let's say your planet is in a star system made of three stars like so:

One is a yellow star orbiting a BIG red giant star at a distance of only a few million kilometers. Your primary is another yellow star, orbiting the other two about 1/3 or 1/4 of a light year away.

One fine day the red giant collapses into a white dwarf star like Sirius. Would this kill your world 1/3 or 1/4 of a light year away?

If not, then the white dwarf's gravity will eventually begin to steal gasses from the yellow star nearby and create an accretion disk around itself. Given a little more time, the disk will collapse into the white dwarf, thereby exploding into a regular Nova. Would this kill your world 1/3 or 1/4 of a light year away?

Any thoughts?

I do need a catastrophe in a system like that or a similar one.

I could work with a simple binary made up of a yellow or orange star with the planet orbiting it, if this primary orbits a Super Red Giant a fair distance away which then collapses into a Super Nova. That would kill anything.