Researchers using the Chandra X-ray Observatory have found that a known pulsar is moving through a supernova remnant at over one million miles per hour.

Okay, this story is pretty neat because of the distances involved. The supernova remnant, G292.0+1.8, is located about 20,000 light-years from Earth. So in order to see how something within the remnant changed position, the team had to compare images taken ten years apart. A side-by-side comparison of the location of the pulsar found that it had traveled about 120 billion miles during this time frame. That turns out to be about 1.4 million miles per hour.

Pulsars are neutron stars that spin rapidly, brightening at a known and usually constant rate. In fact, pulsar timing was used to detect the first exoplanets. And neutron stars form when massive stars run out of fuel. Those stars collapse down so small due to their mass that all of the protons and electrons are crushed together and become neutrons. During formation, neutron stars also explode as supernovae, and sometimes, those explosions can send the star itself moving in a new direction. That appears to be what happened in the case of this particular pulsar.

Of course, this doesn’t explain just how the supernova gives off a directional kick to the star. Scientists have come up with two possible explanations. One involves neutrinos, produced during the supernova, being ejected in an asymmetric pattern, and the other possibility is that dust and stellar debris is ejected asymmetrically. With an asymmetric explosion, conservation of momentum kicks in, and the star has to move in the opposite direction.

This pulsar’s speed means that the amount of neutrinos required would be extreme, so the kick likely came from dust and stellar debris.

This research was presented at last week’s 240th meeting of the American Astronomical Society (AAS) and will be published in The Astrophysical Journal with lead author Xi Long.

More Information

CFA press release

CXO image release

“The Proper Motion of the Pulsar J1124–5916 in the Galactic Supernova Remnant G292.0+1.8,” Xi Long, Daniel J. Patnaude, Paul P. Plucinsky, and Terrance J. Gaetz, 2022 June 22, The Astrophysical Journal