There is hard durability, which is what is asked for by the OP, and then there is damage soak. And then there is durability vs. physical attacks or durability vs. EP, heat, cold, radiation, etc.
No one is questioning Thor's damage soak, his ability to take one hell of a beating before dropping. It is his hard durability that is in question. Thor standing in the sun...awesome display of durability vs. heat and radiation. Not informative, though, about Thor's hard durability vs. physical attacks.
Or at least consider it in a "mystical/godly" way and not someone actually standing in the heart of the sun.
He would not only have to deal with temperature and radiation there, but also pressure and "physical" attacks, far beyond anything the likes of Hulk can deal out.