Stellar Explosion Seen in 3-D

Astronomers have generated a 3-D view at a famed exploding star to reveal how fast the powerful supernova ejected material when it died.

The stunning view comes from new observations of the well-known Supernova 1987A, which as its name suggests exploded in 1987 and was the first naked-eye star explosion seen in 383 years. [Illustration of the 3-D supernova.]

The original blast was not only powerful, it was also more concentrated in one particular direction, according to the new study. This is a strong indication that the supernova must have been very turbulent, supporting the most recent computer models, researchers said.

"We have established the velocity distribution of the inner ejecta of Supernova 1987A," said the study's lead author Karina Kjaer, an astronomer with the European Southern Observatory. "Just how a supernova explodes is not very well understood, but the way the star exploded is imprinted on this inner material. We can see that this material was not ejected symmetrically in all directions, but rather seems to have had a preferred direction. Besides, this direction is different to what was expected from the position of the ring."

The researchers found that the first material ejected from the supernova travelled at a whopping 62 million mph (100 million kph). That is nearly one-tenth of the speed of light or around 100,000 times faster than a passenger jet, researchers said. Even at this breakneck speed, the material took 10 years to reach a previously existing ring of gas and dust puffed out from the dying star, they added.

The new observations also showed that another wave of material is travelling 10 times more slowly and is being heated by radioactive elements created in the explosion.

Such asymmetric behavior was predicted by some of the most recent computer models of supernovae, which found that large-scale instabilities take place during the explosion. The new observations provide the first direct confirmation of such models.

Supernovas are the spectacular finale for massive stars that, once arriving at the end of their life, detonate to expel vast quantities of material. Such stars are larger than our sun, which will end its days in a more subdued manner.

Supernova 1987A, however, is one such star explosion and is located in the nearby Large Magellanic Cloud, a satellite galaxy of our own Milky Way. Because of its relative closeness, the supernova has made it possible for astronomers to study the explosion of a massive star and its aftermath in more detail than ever before.

Kjaer and her colleagues used ESO's Very Large Telescope in Chile to measure the speed at which Supernova 1987A flung material outward.

The research will be detailed in the journal Astronomy and Astrophysics.

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