I think neutron star are actually the ones that tend to explode.; and yes that would be cool.

how could u prevent an exploding star?

Actually only stars that have the correct conditions will supernova, these tend to be ones that are very massive to begin with and that use up much of their hydrogen early in their stellar lives. A neuton star is the left over core from a star that exploded, they are created after all the carbon in the star turnes into iron....the star then gets hotter and hotter untill it reaches a stage call "Photodissociation"....It's all kind of a complicated process. Our sun will never go supernova, as it is not nearly massive enough. Also they would know ahead of time that it was coming. But in terms of the game I think that would be cool.

You know, kind of makes you wish they had put in terror stars. Or at least showed us the sort of code required to build one ourselves. I have a horryfying urge to shoot a stars core, causing it to explode somewhat, watching it wipe out a few worlds, seeing a figure stand over the rubble, look around and say "BOOM! headshot!"

Darn it, no terror stars in this one? I usually just used them as super-influence bombs in the first game. Just build 'em up, and set them in your neighbor's star system and BAM! "I like your place more, I'm going to join up with you now". Oh well, I guess I can live without them.

tsk tsk, people people.... do you not know your astronomy? Blue stars are young stars. Yellow and Orange are mid aged and Red giants are old stars. Red giants tend to expand then collapse creating a number of possible endings:

brown dwarf

white dwarf (can't remember if its brown or white that forms from a collapsed star. one of them can form from a star that fails to get a good reaction going in the begining)

Neutron star (essentially a super dense dark mass that just shoots off unimaginable levels of gamma radiation

pulsar (a spining neutron star, I believe these can even pump out even more gamma radiation and even explode)

(neutron and pulsars would sterilize and fry anything organic within tens of light years distant. They would be a serious threat to intersteller travel)

blackhole extremely rare but now proven to actually exist. essentially the mass of a sun condensed to the size of a ping pong ball. creating massive gravity that can influence time and space (time and space are influenced by gravity. Einstien spent his whole life figuring this out.) it essentially creates an event horizon that sucks in light and matter and then spits it back out at its poles. The center of each galaxy has a massive cluster of stars tightly packed together with a blackhole or more at the center (or so goes the theory). galaxies tend to shoot light, radiation and matter from its center into deep space. it is believed that it is blackholes at the center of the galaxy that hold it all together.

of course there is the good ol nova and supernova and ...one level higher than that ..meganova..can't remember what it is called. This is when an old star doesn't hold form after collapse. It just explodes and obliterates everything for many light years around as well as release an insane amount of radiation. Remember war of the worlds? when people were hit by the aliens "death rays" they went all dust bunny. This is what would happen to you if you were in a nearby solar system. Gives you some perspective of the power of a star. Lets hope Alpha Centuri never goes boom or we're extinct. Of course when a star dies the matter left over forms another star down the line and thus the cycle of the universe of death and rebirth goes on and on.
Of course anyone who knows better feel free to add corrections as I'm trying to remember all this off the top of my head.

i have never played Masters of Orion >< so yah