Nibiru in Nasa terms is called- G1.9+0.3 and they are stating that it's a supernova. They anounced it about six months ago saying that it is in fact in the Milky Way Galaxy about 25,000 light years from Earth .
http://en.wikipedia.org/wiki/Supernova_remnant_G1.9+0.3
http://chandra.harvard.edu/photo/2008/g19/
http://chandra.harvard.edu/photo/2008/g19/zoom.html