Starship Asterisk*

I found a general discussion of this question here

I don't remember which one, but an early mass extinction did coincide in time with a near-by super nova blast. That's very interesting, Bilderback. I am not at all convinced that an asteroid crashing into earch was the cause of the mass extinction at the end of the Permian period that killed off as...

What would happen if there was a super nova closer to home? Mightn't one explain the mass extintions that occurred during Permian-Triassic event?