There's only 1 star, Spica, within that envelope that could go nova, and thats 260 ly away (~847 pc) and isn't big enough to cause an extinction level event at that distance (it would have to be less than 25 ly)

Gamma Ray bursts are much rarer than supernovae, but can be fatal up to 7,000 ly, again howeverwe would have to be "right in the beam" to be affected, Phil Plait the astronomer has calculated that the odds of this happening in your lifetime are about 14,000,000,000 to 1.

Don't worry about it.