Neutron Star ‘Glitch’ Reveals Engine That Powers Rotation

(CN) – A “glitch” in a neutron star 1,000 light-years from Earth offered astronomers the first-ever glimpse into the forces generating rotation for the universe’s most dense objects.

The Vela Pulsar, a neutron star corpse left from a titanic stellar supernova explosion, shoots through space powered by a jet emitted from one of the neutron star’s rotational poles. (NASA / CXC / PSU / G.Pavlov et al.)

Neutron stars rotate swiftly and regularly as they travel through the cosmos. But astronomers have long sought answers for why some neutron stars occasionally spin at greater speeds and then suddenly come to a halt.

In a study published Monday in Nature Astronomy, researchers said their first-ever view inside neutron star Vela Pulsar reveals how internal forces cause the star to spin faster.

Paul Lasky, a researcher with Monash University and the ARC Centre of Excellence for Gravitational Wave Discovery, said in a statement that “glitches” come from three components inside a neutron star.

“One of these components, a soup of superfluid neutrons in the inner layer of the crust, moves outward first and hits the rigid outer crust of the star, causing it to spin up,” Lasky said. “But then, a second soup of superfluid that moves in the core catches up to the first causing the spin of the star to slow back down.”

Internal images of Vela Pulsar – collected in 2016 by study co-author Jim Palfreyman of the University of Tasmania – were the first to offer clues on why the slowdown occurs.

“This overshoot has been predicted a couple of times in the literature, but this is the first real time it’s been identified in observations,” Lasky said.

One such prediction came from study co-author Vanessa Graber of McGill University, the astronomers said in their statement.

A “glitch” on Vela Pulsar occurs once every three years. It is one of only 5% of neutron stars that are known to glitch.

Study lead author Greg Ashton said in the statement that it’s unclear why the neutron stars’ rotation slows just before the glitch only to begin spinning again with violent speed.

“We actually have no idea why this is, and it’s the first time it’s ever been seen,” said Ashton. “It could be related to the cause of the glitch, but we’re honestly not sure.”

Ashton said he hopes the study will inspire other astronomers to generate new theories on neutron star glitches.

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