Well, to be fair, the movie never explains which star it is. A supernova that destroys a planet as depicted in the movie would need to be in the solar system. If Alpha Centauri A blew up, we wouldn't notice anything, at least not for the next 4 years. So it is safe to say it was in fact the Romulan star. Even if it's called Hobus. We call our sun Sol, yet we live on Earth. It's not the Earth star or Terran star.
Except that Romulans are a warp-capable civilization. . . You'd think that they would know that their own star was going supernova. . .especially since there would be signs of it for thousands of years before it blew, and they would have evacuated (for example. . . the star would have expanded to thousands of times its size, maybe engulfed a planet or two, had out-gassing, changed its spectrum -- that sort of thing). . .instead of waiting for an old Vulcan to save them. . . for a movie that some people claim is dumb, the writers sure thought that viewers would think of this type of stuff and not need it spoon-fed to them. . .
~FS
