What happens when a neutron star suddenly spins faster?

A team of astronomers including Dr Willem van Straten of the Institute for Radio Astronomy and Space Research reported the first direct observations of a pulsar glitch.

Alteration of the magnetosphere of the Vela pulsar during a glitch
Nature 556, 219–222 (2018)

A pulsar is a class of neutron star, which are extreme in every way imaginable. They weigh more than the Sun but are smaller than Auckland in diameter, making them more dense than an atomic nucleus, with gravitational fields second only to black holes.  They boast the most powerful magnetic fields in the Universe and they can spin faster than the blades in a kitchen blender. Like cosmic particle accelerators, jets of matter and antimatter stream from their magnetic poles at close to the speed of light.  The beams of radiation from these jets sweep across the Galaxy with each rotation of the star and, like a distant lighthouse, are observed here on Earth as periodic trains of pulses.

With so much mass and speed, it’s hard to imagine that anything could alter the rotation of such a formidable celestial flywheel; however, pulsars are known to very suddenly speed up, or glitch.  Exactly how suddenly was unknown before Vela was caught in the act, and it appears that the glitch took place in less than 6 seconds.  The glitch also temporarily disrupted the streams of radiation produced by Vela’s magnetic field.

“These observations leapfrog current theory,” says Willem. “There are no models that describe the interaction between the superfluid interior, the solid crust, and the magnetosphere of a neutron star on such short time scales.”

Using AUT’s Warkworth Radio Astronomical Observatory, Willem and PhD student Natalia Primak plan to make further progress in this area by regularly monitoring the small handful of radio-emitting magnetars.

The result was also reported in various media outlets on 12 April:

Kiwi scientists have witnessed a one of a kind stellar event as Vela Pulsar star glitches
One News NZ

Waiting four years for a glitch in space
Interview with Jesse Mulligan on Radio NZ

What happens when a neutron star ‘glitches’
Delwyn Dickey for Stuff.co.nz

Nature podcast

Astronomy: Dr Willem van Straten
Interview with Bryan Crump on RNZ Nights (14 May 2018)