Thor #8 came out yesterday and with it the identity of our new Thor. The beginning of this run saw a mystery woman pick up Mjolnir and claim the powers and mantle of everyone's favorite Asgardian. For the first seven issues, readers had no idea who grabbed that hammer, but now we know.
It's Dr. Jane Foster, a longtime character in the Thor comic, writer Jason Aaron says:
Jane Foster has been part of the Thor comics and the Thor mythology from almost the very beginning. The very act of picking up this hammer, of becoming Thor, is killing her. Where we go from here is the real story.
Foster is played by Natalie Portman in the movie franchise. So, if Hemsworth ever decides to leave, Marvel has an awesome leading lady to take over.