How much would Mjolnir weigh if it were made from a dying star?

https://www.youtube.com/watch?v=TbdH2...

Given the disclaimer that it's not made from a dying star, well....

Physics is always fun when it smacks into the unreality of superheroes. I love superheroes. But it does amuse me, the disjunction.

Like when Superman or the Flash start to move at a significant fraction of the speed of light, the air compression should set off explosions of plasma, etc. Or when Iron Man gets smacked around by some super-strong person, Tony Stark should get turned into mush, because even if the suit is unharmed, when he is sent flying and crashes into something, the acceleration should pulp him inside the suit. Or when Batman saves himself out of a fall by using one of his grappling guns for a last second save, the gun should be ripped out of his hand, or if it's magnetically secured to his glove, his arm should be torn out of the socket. Or Captain America's shield--in the movie, it's explained that vibranium absorbs and nulllifies kinetic energy, which would explain how it's great for saving Cap from things like the explosive shockwave of that dying alien in the Avengers, but does not explain how the shield can still smack into anyone and hurt them, because the impact should be nulled.

Ah yes, it's always interesting imagining how they are incompatible, superhero physics and real physics, and trying to figure out how they could be made to converge without too much handwavium.