So, imagine an atmosphere-less planet, tidally locked to a sun-like star. How close to the star can the planet be before its dark side becomes too hot?
I imagine that at some point the rocks on its sunlit side will melt and evaporate so that the dark side would experience rocky precipitation, is it true?
Also, at some point the atmosphere of the star itself would engulf the planet.
But at which point these effects will make the conditions on the dark side unbearable?