Betelgeuse

AKA:  Alpha Orionis
Class:   Star (Red Supergiant, M2Iab)
Distance:  6.08e+15 km (643 ly)

Facts:

8th brightest star in the night sky and 2nd brightest star in orion, although it occasionally outshines Rigel.
A semiregular variable star.
If it were at the center of our Solar System, its surface would extend past the asteroid belt possibly to the orbit of Jupiter or beyond.

Details: