W49B isn't a ring, though. It's a sloppy barrel shape that indicates an uneven, asymmetrical eruption, hinting that the original star didn't go peacefully into this good night.
ANALYSIS: Mystery Behind Supernova SN 1006 Solved?
And as for the star? It's nowhere to be found - which is in itself strange. Supernova remnants usually have some form of neutron star at their centers, the wildly-spinning, ultra-dense cores of dead massive stars. But even after searching for one, scientists have found no such object at the center of W49B. This could mean that there's a very different sort of stellar corpse lurking there - a black hole.
If that is indeed the case, then this would be the galaxy's newest black hole - at least as far as what's been discovered so far. A mere thousand years old, an alleged black hole at the heart of W49B would have just been born in the night sky around the same time that Vikings were first setting foot on North American shores.
A long time ago for us, yes, but barely yesterday in astronomical terms.