Geoff the Medio wrote:
There is some overlap in the stellar configurations that (real universe) can produce both events, though there are several varieties of supernovas that arise from situations that can't produce a nova. I'd like to be reasonably consistent with reality in this case... (I'm not an astrophysicist, but I believe novas require a white dwarf accreting gas from a binary companion, which can also cause supernovas, but supernovas can also occur if a very large star collapses. Novas leave a white dwarf after - so can recur periodically - but supernovas leave a neutron star or black hole)
Supernova will occur after a large star collapses, but first the star will expand into a red giant. When hydrogen is used up other elements are used for fusion, which release energy faster forcing the star to expand. When the star has no fuel left for nuclear fusion the fusion stops, reducing the pressure acting against the gravity of the star, this causes the star to collapse, get hotter and explode. There are no red giants in the game, so there would be no supernovae. In real life the different types (blue, yellow, red) of stars are different masses, but in this game the different colours are different ages, since Solar Rejuvenator building will change the colours. Larger stars in real life are hotter and 'live' for less time - so they are all young as they die young. Smaller cooler stars live thousands of times longer than large stars, so they are mostly older (but they could be young or old). Switching between the types would require changing the mass of the stars. Also, Solar refers to the Sun not to stars in general, the building should be a Stellar Rejuvenator. I am also not an Astrophysicist, but I do have qualifications which would let me be.
The game is not realistic in many ways, but so what? There are so many different advanced aliens and space monsters messing with the stars and planets in FreeOrion that I doubt if any of them are still in the state they were when they were formed.
I think supernova should be in the game, but only occasionally. They should destroy all the planets in the system they occur in and maybe mess up the starlanes too. Each of the systems in the game connected by starlanes are really far away from each other. The galaxy is tens of thousands of lightyears across. 1 uu in the game is more than 10 lightyears (maybe 50 lightyears). The other systems would not suffer any physical damage, but could have very increased levels of radiation - like X-rays and gamma rays, so colonies and spaceships could suffer, but it would be many turns later. If the effects travelled down starlanes it would all be much quicker. I think it might be fun if all the spacemonsters ran away from the supernovae, like a stampede. For graphics I think making the star much brighter, followed on successive turns by an expanding 'wave' of energy would be good. For the sidepanel A really bright star followed by a blackhole or neutron star with expanding dust which eventually expands off picture leaving a standard neutron star or black hole graphic after a few turns.
Leaving a neutron star or a blackhole would make sence, for reasons of making them have a game effect an asteroid belt or two should remain, so that outposts can be built to use the neutron star or black hole. Maybe colonies with lots of sheilds should become unihabited asteroid fields, or gas giants could become tiny worlds (they can have solid cores), and everything else is destroyed. Ships should all take a lot of damage, but maybe the very best defences could be enough to survive, since it would be cool to have a ship so tough that it can survive supernova!
Edit - I did some reading... Some types of supernova leave nothing behind. If mass from the companion star of a white dwarf is pulled onto the white dwarf, increasing the white dwarf's mass above the maximum possible mass for a white dwarf a supernova occurs destroying the white dwarf and the companion star. No mention is made of planets.