Oolite Bulletins

A while back I posted about this Circumstellar Habitable Zone simulator:
https://bb.oolite.space/viewtopic.php?f=7&t=12141

It turns out they have more simulations than just that one:
http://astro.unl.edu/animationsLinks.html

Enjoy!

I remember that, way back in the day, I used to be almost obsessed with StarGen. It basically takes a random seed and uses that to construct hypothetical planetary systems, orbiting either actual stars in the galaxy or a fictional one with custom parameters. I'd spend hours on that thing, not really understanding everything it spat out at me, but with my imagination fired by every new system that it created.

There was also the Earth Impact Effects Calculator, though I think it used to be on a different website several years ago.