JFYI, the negative 'system - movement towards center' value didn't work.
No repulsion for Novas then.
Damaging sectors for the infestation sounds good, but it might take a bit of work to do it. Let me see..
Stellar core fragments as I have them now destabilize local warp points as well as are destructive and pull ships toward them at 1 sector per turn. This at least makes them mildly interesting.
Green giants (Ho, ho, ho! Green Giant!
) really don't exist as far as I know, though blue giants do (very VERY large stars that are short lived; very hot too). But I have made them cause massive sensor interference and shield interference, as well as do the pulling 1 sector in per turn thing. The greenies don't have a destructive center though..
I also gave the burned out star the same asteroid configuration as the asteroid system in stellartypes.txt. This will generate asteroids in this system, but there won't be a star in it.
Blackholes are now of two types: normal, and powerful. The powerful one moves you in 4 sectors per turn.
The spatial ruptures are also of two types: normal, and powerful. The powerful one moves you 4 sectors in a random direction per turn, but the center is also destructive. (So keep your lucky dice handy!)
I am also trying to revamp each of the nebulaes so they are unique from one another (i.e., some interfere scanners, others shut down shields, and some do both).
Plus some other stuff.