It's actually kinda cool, because a star goes nova when it runs out of elements with a lower atomic number than iron to burn. It starts with the easiest, hydrogen and helium, and keeps shifting down, sort of desperately burning whatever it's got to keep the fires lit. When it hits iron, it costs more energy to fuse it than it gets back from the process, and it all collapses catastrophically. Adding a bunch of iron to a star wouldn't cause it to stop fusing hydrogen and start eating the iron, AFAIK, so the science was squiffy there, but at least someone cracked a book here!
Even a kinda/sorta handwave to science on the way by in a comic like this is fun for me, as a science-fan, as well as a comics-fan.