NASA caught a dead star spewing antimatter
Did you know? Pulsars are a rapidly spinning type of neutron star
Asmall pulsar belched out an enormous beam of matter and antimatter particles that streamed for 40 trillion miles across the Milky Way. Astronomers detected the cosmic particle trail in images captured in X-rays by NASA’S Chandra X-ray Observatory in space and in optical light by the Gemini North telescope in Hilo, Hawaii. Observations of X-ray filaments emitted by pulsars are rare – to date only a handful have been detected.
Pulsars are dense, shrunken remnants of giant collapsed stars that emit radiation pulses as they spin, and they have powerful magnetic fields that are generated by their rapid rotation. This pulsar, known as
PSR J2030+4415, spins about 1,600 light years from Earth and is relatively tiny – just ten miles in diameter, about the size of a city.
This fast-spinning pulsar travels through space at about 500,000 miles per hour and rotates about three times per second; as it spun around, charged particles escaped as a streaming filament that was then captured in telescope images. The huge scope of
PSR J2030+4415’s particle stream could explain why the Milky Way contains so many positrons, the antimatter counterparts of electrons.
Images of PSR J2030+4415 captured in 2020 and 2021 revealed the extraordinary length of the filament and also showed particles in a cloud-like halo surrounding the pulsar. “It’s amazing that a pulsar that’s only ten miles across can create a structure so big that we can see it from thousands of light years away,” said Martijn de Vries, a postdoctoral scholar at the Kavli Institute for Particle Physics and Cosmology at Stanford University. “With the same relative size, if the filament stretched from New York to Los Angeles, the pulsar would be about 100 times smaller than the tiniest object visible to the naked eye.”
Pulsars have powerful magnetic fields that usually confine whipping winds of charged matter and antimatter particles close to the collapsed star. As a pulsar travels through space, its magnetic field interacts with nearby solar winds and gases, which build up as they travel ahead of the pulsar like a wave of water pushed along by the prow of a boat. About 20 to 30 years ago, something disrupted the momentum of the wave produced by
PSR J2030+4415 and the pulsar slammed into it; the collision likely triggered a particle leak and sprayed a stream of particles into space. “The pulsar wind’s magnetic field linked up with the interstellar magnetic field and the high-energy electrons and positrons squirted out through a nozzle formed by connection,” said Roger Romani, a physics professor at the Kavli Institute.
Most of the matter in the universe is normal matter; antimatter is matter with the opposite electric charge. In pulsars, a combination of speedy rotation and strong magnetic fields creates a perfect storm of powerful radiation and particle acceleration, producing paired electrons and positrons – matter and antimatter. Astronomers previously detected pockets of antimatter in our home galaxy in the form of positrons, but the origins of this local antimatter have been elusive. However, with the discovery of
PSR J2030+4415’s staggeringly long trail, the study authors suspect that this tiny pulsar could be a source.