re: #4 austin_blue

This is all Beowulf Shaeffer investigating a Neutron Star, and Louis Wu investigating the Ringworld, innit?

It’s from an Analog Science Fiction/Fact cover story about emergency evacuation from a star system about to go nova.
I don’t remember the title or author, but during Stanley Schmidt’s editorship .
I have the volume somewhere in my years of collection of Analog SF.
As the star’s fusion works its way up to silicon the group knows they have approximately 24 hours to leave the system & travel several hundred light years before the supernova explosion.