Nuclear explosions on a neutron star feed its jets

This artist’s impression depicts how nuclear explosions on a neutron star feed the jets blasting off from its magnetic polar regions.

When in orbit with another star, the neutron star’s intense gravitational field can ‘suck’ material away from the nearby companion. The material swirls towards the collapsed object, circling it, forming a disk, and ultimately plunging to the surface. The crashing gravity on the neutron star’s surface violently compresses the accumulated material (consisting mostly of hydrogen) causing a runaway nuclear explosion. This in turn triggers the jets to suddenly intensify and eject particles into space at very high speed.

A neutron star that is swallowing material from a nearby companion is a powerful celestial source of X-ray and radio light. Scientists have used instrumentation on board of ESA Integral satellite and CSIRO's Australia Telescope Compact Array (ATCA) of radio telescopes to monitor one of these intriguing systems over many hours.

For the first time, they observed a clear link between bursts of X-rays and peaks in the radio signal. It revealed how the explosion triggers an increase in material flowing into the jet that is launched into space at one-third the speed of light. This result opens a new window to investigate how jets form on neutron stars and in other celestial objects, and to establish whether there is a direct connection between how quickly an object spins and the power and speed of its jets.

[Image description: In the foreground, at the centre right, there is a very bright white ball, representing the neutron star. White/purple filaments are streaming out from its polar region. The ball is surrounded by a hazy white larger sphere, the corona, and further out by a disk with concentric bands of different colours, going from white in the inner disk to orange in the middle and to red-magenta in the outer region. An orange band connects the outer part of the disk to a large yellow-orange-red section of a sphere in the top left corner. This represents the star companion of the neutron star, that is feeding the disk around the bright white spherical body.]