Step aside, black holes; there’s a new shooter in town. Astronomers have found that neutron stars can create jets of material just as powerful as their considerably more massive counterparts, suggesting an unknown process is taking place in these extremely dense supernova remnants.
Some neutron stars, which are the collapsed cores left behind after a star explodes, were already known to have jets of super-heated matter firing from their poles. But they were thought to be puny in comparison to that of a black hole, only appearing visible when the star was gathering large amounts of material from a more normal companion star. Black holes, by comparison, can fire out powerful jets even when consuming only a small amount of material.
However, this latest discovery by the Netherlands Institute for Radio Astronomy (ASTRON), the International Centre for Radio Astronomy Research (ICRAR) in Australia and other institutions, suggests otherwise. They found that neutron stars, which contain 1.5 times the mass of the Sun but are no more than 10 to 15 kilometers (six to nine miles) across, could fire out jets approaching the speed of light without gobbling large amounts of material from another star.
"From what we had seen previously, black holes were previously considered the undisputed kings of forming powerful jets, even when they were only fed by a little bit of material from their companion star," said Adam Deller of ASTRON in a statement. "But our observations suggest its jets are nearly as strong as you’d expect from a black hole." The research was published in the Astrophysical Journal.
Astronomers used the Karl G. Jansky Very Large Array (VLA) in New Mexico to make the findings, studying the pulsar binary system PSR J1023+0038, 4,500 light-years away. Its rapidly rotating neutron star, known as a millisecond pulsar, spends years in a sedate state when it doesn't gather much material from its companion, leading astronomers to predict it would produce a relatively weak jet.
Instead, they found it was creating a jet almost as strong as one from a black hole. Two other pulsars in similar states, known as “transitional” systems, were also found to be producing similarly powerful jets.
"It's surprising, and it tells us that something we hadn't previously suspected must be going on in some systems that include a neutron star and a more-normal companion star," said Deller.
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