Bad Astronomy reports astronomers have spotted a potential Type Ia supernova in our own galaxy. This is a white dwarf that orbits a normal star like the Sun, it draws material off and as this matter piles up on the dense core of the white dwarf it can eventually detonate like a stellar thermonuclear bomb. The object is about 25,000 light years away and may go supernova within a couple of thousands of years, or even longer, it would then appear in the sky brighter than Venus.
Called V445 Puppis, in November 2000 it underwent an explosive event: not a supernova, but a regular nova, the detonation of small (in cosmic terms) amount of material. Still, it ejected a lot of matter — several times the mass of the entire Earth — at very high speed, about 24 million kilometers per hour (14 million mph). That would reach from the Earth to the Moon in one minute flat. Over the course of several years, astronomers have taken images of the expanding debris, and the change — seen in the picture above — is dramatic, lovely, and terrifying.
The debris did not expand spherically because the two stars are in a tight orbit, circling each other rapidly. The matter drawn off the normal star forms a thick disk around the white dwarf. When the material on the surface exploded, it couldn’t go through the disk, so it went up and down, above and below the disk. Over time it forms what’s called a bipolar structure, because it comes out of the poles of the star. We see lots of similar bipolar objects, but not usually in a system that’s about to go bye-bye.