The Sun’s not going to blow up
In any science fiction story I’ve read (or science fiction movie or TV show that I’ve seen) that talks about death of the Sun. I’ve always heard references to Earth’s sun “going nova”. I’ve read about this even in Asimov’s stories. In most cases, they’re talking about a supernova. But here’s the thing. The Sun is not going to blow up. Even if the writers were talking about an actual nova, they’re still wrong. Here’s why:
Our Sun is a yellow dwarf star (more precisely known as a G-type main-sequence star), and doesn’t have enough mass to undergo a supernova explosion (type IIa). You need a star that’s at least nine times the Sun’s mass for a supernova explosion. If we’re simply looking at a nova (type Ia), then the Sun doesn’t have a companion to draw matter from when it turns into a white dwarf. So no matter which way you look at it, the Sun is not going to blow up. It’s just going to be really, big and red and will eat the Earth. Unless the Earth moves outward due to the Sun losing mass. Finally the Sun with eject its outer layers and turn into a white dwarf. See? No blowing up. I don’t know why some science fiction authors still talk about the Sun “going nova”. Maybe it’s because it sounds more dramatic.
If anyone has read a science fiction story (or seen a science fiction movie or TV show) that talked about the death of the Sun/Earth and did so realistically, then let me know.