Let’s say we have a Star system with a gas giant about 30 AU from the local sun. This is way too far for this particular sun to warm any moons to habitability (unless life inhabits subsurface oceans) but what if the planet could act as a sun?
We have a moon called Pontus III, about twice the mass of the Earth’s moon and rocky. It orbits even closer to the gas giant Pontus than Io does to Jupiter. Because it’s orbit is ever so eccentric, this places it under huge tidal stresses, which cause increased vulcanism and warms the planet sufficiently for liquid water to exist on the surface.
Could this arrangement work to make Pontus III habitable?