A pulsar in the G292.0+1.8 supernova remnant moves at more than a million miles per hour, as seen in the Chandra image with an optical image from the Digital Sky Survey. Pulsars are rapidly spinning neutron stars that can form when massive stars run out of fuel, collapse and explode. Sometimes these explosions generate a “kick,” which sent this pulsar racing through the remnants of the supernova explosion. Additional images show a closer look at this pulsar in X-rays from Chandra, who observed it in both 2006 and 2016 to measure this remarkable speed. The red crosses in each panel show the position of the pulsar in 2006. credit: X-ray: NASA/CXC/SAO/L. Xi et al.; Optical: Palomar DSS2
- a[{” attribute=””>pulsar is racing through the debris of an exploded star at a speed of over a million miles per hour.
- To measure this, researchers compared NASA Chandra X-ray Observatory images of G292.0+1.8 taken in 2006 and 2016.
- Pulsars can form when massive stars run out of fuel, collapse, and explode — leaving behind a rapidly spinning dense object.
- This result may help explain how some pulsars are accelerated to such remarkably high speeds.
A pulsar in the G292.0+1.8 supernova remnant is moving at more than a million miles per hour. This image contains data from NASA’s Chandra X-ray Observatory (red, orange, yellow and blue), which was used to make this discovery. The X-rays were combined with an optical image from the Digitized Sky Survey, a ground survey of the entire sky.
Pulsars are rapidly spinning neutron stars that can form when massive stars run out of fuel, collapse and explode. Sometimes these explosions generate a “kick,” which sent this pulsar racing through the remnants of the supernova explosion. An inset gives a closer look at this pulsar in X-rays from Chandra.
To make this discovery, the researchers compared Chandra images of G292.0+1.8 taken in 2006 and 2016. A pair of Supplementary Images shows changes in the position of the pulsar over a 10-year period. The change in source position is small because the pulsar is about 20,000 light-years from Earth, but it traveled about 120 billion miles (190 billion km) in this period. The researchers were able to measure this by combining high-resolution images of Chandra with the careful technique of examining the coordinates of pulsars and other X-ray sources using precise positions from the Gaia satellite.
The team calculated that the pulsar supernova is moving from the remnant’s center to the bottom left at at least 1.4 million mph. This speed is about 30% higher than the previous estimate of the pulsar’s speed which was based on an indirect method, measuring how far the pulsar is from the center of the explosion.
The newly determined speed of the pulsar indicates that G292.0+1.8 and its pulsar may be much smaller than astronomers previously thought. The researchers estimate that the G292.0+1.8 eruption may have occurred about 2,000 years ago as seen from Earth, and not 3,000 years ago as previously calculated. This new estimate of G292.0+1.8’s age is based on extrapolating the pulsar’s position backwards in time so that it coincides with the center of the explosion.
At that time several civilizations around the world were recording supernova explosions, leaving open the possibility that G292.0+1.8 was directly observed. However, G292.0+1.8 is below the horizon for most Northern Hemisphere civilizations that would have observed it, and there are no recorded instances of supernovae observed in the Southern Hemisphere in the direction of G292.0+1.8.
In addition to learning more about the age of G292.0+1.8, the research team also investigated how the supernova gave the pulsar its powerful kick. There are two main possibilities, both of which do not involve material being ejected equally in all directions by the supernova. One possibility is that the neutrinos produced in the explosion are ejected asymmetrically from the explosion, and another that the debris from the explosion is ejected asymmetrically. If the material has a preferred direction then the pulsar will be kicked in the opposite direction because of the principle of physics called conservation of momentum.
This latest result would exceed the amount of neutrino asymmetry needed to explain the high speed, supporting the explanation that the asymmetry in the debris of the explosion gave the pulsar its kick.
The energy provided by this explosion to the pulsar was enormous. Although only about 10 miles across, the pulsar has 500,000 times that of Earth and is traveling at 20 times the speed of Earth orbiting the Sun.
The latest work by Xi Long and Paul Pluchinsky (Center for Astrophysics | Harvard & Smithsonian) on G292.0+1.8 was presented at the 240th meeting of the American Astronomical Society in Pasadena, CA. The results are also discussed in a paper that has been accepted for publication in The Astrophysical Journal. The other authors of the paper are Daniel Patnaud and Terence Getz, both from the Center for Astrophysics.
Reference: “Proper motion of pulsar J1124-5916 in the galactic supernova remnant G292.0+1.8” Shi Long, Daniel J. Patnaude, Paul P. Pluchinsky and Terence J. Approved by Getz, The Astrophysical Journal,
arXiv:2205.07951
NASA’s Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.
