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W49B Animations
Click for low-resolution animation
Tour of W49B
Quicktime MPEG With closed-captions (at YouTube)

The supernova remnant known as W49B is, let's say, a bit unorthodox looking. Many supernova remnants appear rather spherical in shape. This is in large part because astronomers think that most supernovas explode more or less evenly in all directions. W49B, however, is an exception to that rule. Researchers instead think that the star that created W49B ejected more material at higher speeds from its poles than from its equator during its explosion. The result is this unusual barrel-shaped remnant we see today. While most supernovas leave behind a dense rotating core called a neutron star, there is no evidence that one is present within W49B. This and other evidence suggest that an even more exotic object, that is, a black hole, was produced during the explosion. Since W49B's explosion occurred about a thousand years ago as seen from Earth, this means this may be the most recent black hole formed in our Milky Way galaxy.
[Runtime: 01:13]

(Credit: NASA/CXC/A. Hobart)



Click for low-resolution animation
A Study in Supernovas
Quicktime MPEG With closed-captions (at YouTube)

Like the famous detective Sherlock Holmes, astronomers have to be good at solving puzzles by piecing together clues and evidence. When scientists using the Chandra X-ray Observatory noticed the strange, distorted shape of this supernova remnant, they knew something unusual had taken place. After scouring through their data and arguing against other possibilities, astronomers realised they may have uncovered a dark secret lurking within this picture - a young black hole!

The supernova explosions that tear apart massive stars normally blast away material evenly in all directions and leave behind a symmetrical bubble (the same on both sides). However, in this supernova, material from the north and south poles of the star (yes, stars have poles, too!) was blasted out much faster than anywhere else. The resulting barrel-shaped remnant gave astronomers their first clue that this star's life ended in an unusual way.

Most of the time when a star goes supernova, the remaining core is squashed down into a tiny ball called a neutron star. Neutron stars normally give off X-ray radiation, which astronomers can photograph using special telescopes. But a careful search of the data showed no X-ray radiation or other evidence for a neutron star. This means an even more exotic object was probably formed during the explosion - a black hole! If this turns out to be correct, it'll be the youngest known black hole in our entire Galaxy, at just 27,000 years old!
[Runtime: 02:02]

(Credit: NASA/CXC/April Jubett)


Return to W49B (January 28, 2013)