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NASA’s Chandra Captures Pulsar in an X-ray Flash

The remnant of the G292.0 + 1.8 supernova contains a pulsar moving at more than 1 million miles per hour, as seen in the Chandra image, along with an optical image from the Digital Sky Survey. Pulsars orbit rapidly around neutron stars that can form when massive stars run out of fuel, collapse and explode. These explosions sometimes produce a “kick,” causing this pulsar to race through the remnants of a supernova explosion. Additional images show a close-up of this pulsar in X-rays by Chandra, which he saw in 2006 and 2016 to measure this impressive speed. Red crosses in each panel show the location of the pulsar in 2006. Credit: X-ray: NASA/CXC/SAO/L. Shi 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.

The G292.0 + 1.8 supernova remnant contains a pulsar 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. X-rays are combined with an optical image from the Digitized Sky Survey, a ground survey of the entire sky.

Pulsars spin neutron stars quickly. They can form when massive stars run out of fuel, collapse and explode. These explosions sometimes produce a “kick,” prompting the pulsar to race through the remnants of the supernova explosion. The inset shows a close-up of this pulsar in Chandra’s X-rays.

To make this discovery, the researchers compared Chandra images of G292.0 + 1.8 taken in 2006 and 2016. A pair of complementary images show the change in the pulsar’s position over 10 years. The source location shift is negligible because the pulsar is about 20,000 light-years from Earth, but it has traveled about 120 billion miles (190 billion km) during this time. The researchers were able to measure this by combining high-resolution Chandra images with precise technology to verify the coordinates of the pulsar and other X-ray sources using precise positions from the Gaia satellite.

Pulsarposities, 2006 in 2016

Pulsar-sites, 2006 in 2016. Credit: X-ray: NASA/CXC/SAO/L. Shi et al.

The team calculated that the pulsar was moving at least 1.4 million miles per hour from the center of the supernova remnant to the lower left. This speed is about 30% higher than the previous estimate of the speed of the pulsar, which was based on an indirect method, by measuring how far the pulsar is from the center of the explosion.

The newly determined speed of the pulsar suggests that G292.0 + 1.8 and the pulsar may be much smaller than astronomers previously thought. The researchers estimate that G292.0 + 1.8 could have erupted about 2,000 years ago, as seen from Earth, rather than 3,000 years ago as previously calculated. This new estimate of the age of G292.0 + 1.8 is based on extrapolating the pulsar’s location back in time to coincide with the center of the explosion.

Many civilizations around the world recorded supernova explosions at the time, opening up the possibility of directly observing G292.0 + 1.8. However, G292.0 + 1.8 is below the horizon for most civilizations in the Northern Hemisphere that you have observed, and there are no recorded examples of a supernova observed in the Southern Hemisphere toward G292.0 + 1.8.

G292 + 1.8 close-upG292 + 1.8 close-up

Close-up of Chandra’s image center for the G292+1.8. The direction of motion of the pulsar (arrow) and the position of the center of the blast (green oval) are shown based on the movement of debris seen in the optical data. The position of the pulsar was extrapolated 3000 years ago and the triangle represents the uncertainty in the induction angle. The similarity of the induction site to the epicenter of the explosion gives an age of about 2000 years for the pulsar and G292 + 1.8. The center of gravity (crossroads) of the X-ray elements detected in the debris (Si, S, Ar, Ca) is opposite the center of the explosion of the moving pulsar. The asymmetry in the debris in the top right corner of the explosion kicked the pulsar to the bottom left, maintaining momentum. Credit: X-ray: NASA/CXC/SAO/L. Shi et al.; Optical: Palomar DSS2

In addition to learning more about the age of G292.0 + 1.8, the research team also studied how the pulsar’s supernova gave its powerful kick. There are two main possibilities, both of which imply that material is not being ejected evenly in all directions from the supernova. One possibility is that neutrinos The output of the explosion is ejected asymmetrically from the explosion, the other is that the debris produced by the explosion is ejected asymmetrically. If matter had a preferred orientation, the pulsar would be pushed in the opposite direction due to a physical principle called conservation of momentum.

The amount of neutrino asymmetry needed to account for the high velocity in this latter result would be extreme, supporting the interpretation that the asymmetry in the debris from the explosion gave the pulsar its kick.

The energy transferred to the pulsar by this explosion was enormous. Although the pulsar is only about 10 miles in diameter, the pulsar has a mass 500,000 times that of Earth, and it travels 20 times faster than Earth’s speed in orbit around the sun.

The latest work by Xi Long and Paul Plucinksky (Astrophysics Center | Harvard & Smithsonian) on G292.0+1.8 was presented at the 240th meeting of the American Astronomical Society in Pasadena, California. The results are also discussed in a paper accepted for publication in The Astrophysical Journal. The other authors of the paper are Daniel Patnaud and Terence Gaetz, both of the Center for Astrophysics.

Reference: “Proper motion of pulsar J1124-5916 in the galactic supernova remnant G292.0 + 1.8” by Xi Long, Daniel J. Patnaude, Paul P. Plucinsky and Terrance J. Gaetz, Accepted, Astrophysical Journal.
arXiv: 2205.07951

NASA’s Marshall Space Flight Center manages the Chandra program. The Chandra X-ray Center at the Smithsonian Astrophysical Observatory controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.

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