What happens to the Heroes when the empire they work for is defeated?

I finished off a rival earlier and noticed they had a few heroes just before I defeated them so I kept an eye on the market to pick them up but they never appeared (10turns later at least).

It takes 20 turns for Heroes to recover when they are defeated, so it might be that.

Yea, may be a good idea that heroes from eliminated empires, once the owner is eliminated become available to all remaining players in the next turn, via quests, enslaved by the conqueror, accelerating academy heroes offer or simply added to the market.

Really never know what happened to them (may be they're executed as traitors? Which make sense in elimination by conquest, but noway in elimination due to bankruptcy or akin)