Strofor: a huge flying piece of once molten rock
This one is a biggie! Strofor is the second largest moon in PE31H. When not taking Santri's super-massive moons into account, it is also the heaviest. Strofor is big enough to have its' own atmosphere. Probably there was one in the past, before evaporating completely due to the surface conditions - namely: the oppressive heat...
For the reasons yet to be discovered, Strofor was once hot enough to cause its' hematite-rich crust to molten, and so rivers of lava covered the whole of the moon's surface. By now, Strofor has cooled down and the lava has solidified, creating enormous trenches and grooves on its' brownish face.
To this day Strofor radiates out the heat from the iron core, that is being kept liquid by Passor's tidal forces. But neither the inner heat, nor the light of PE31H star, even combined, are enough to keep Strofor's lava rivers flowing.