Astronomers observed a jet 20,000 light-years from Earth

Jun 28, 2007 06:59 GMT  ·  By
Artist's impression of a jet of relativistic particles blasting out of Circinus X-1, with a Chandra image (inset) of the jets.
   Artist's impression of a jet of relativistic particles blasting out of Circinus X-1, with a Chandra image (inset) of the jets.

Neutron stars are one of the few ways a star ends its life. They are formed from the remaining of a massive star after it had already exploded into a supernova that condenses into an extremely dense core. They usually have masses 1.35 to about 2.1 times greater than that of our Sun, while being 30,000 to 70,000 times smaller than the Sun.

Astronomers knew that these stars resembled an onion, with multiple overlapping layers of materials, made up of different chemicals concentrated at different depths and just recently found that the surfaces of some neutron stars are much hotter than expected.

A new discovery consolidates the existing knowledge about these intriguing stars. Sebastian Heinz of the University of Wisconsin at Madison is the author of a study that found that the neutron stars, much like black holes, spew very powerful jets of matter in space.

The matter is hurled into space from their poles and the jets are comparable, sometimes even more energetic that the ones put out by black holes. So, it seems that some unique properties of black holes, like the event horizon and lack of physical surface are not absolute requirements for the formation of these jets.

"Gravity appears to be the key to creating these jets, not some trick of the event horizon," said Heinz, who made the discovery using observation from NASA's Chandra X-ray Observatory. The telescope spotted a jet of matter coming out of a system located 20,000 light-years from Earth.

That system was known for having a neutron star spinning around a normal star several times more massive than our Sun, and it's called Circinus X-1. This was the first time a jet was associated with a neutron star.

"In terms of energy efficiency across the universe, this result shows that neutron stars are near the top of the list. This jet is almost as efficient as one from a black hole," said Norbert Schulz, study team member at the Massachusetts Institute of Technology.