Neutron Star With a Tail Like a Comet

Supernova remnant IC 443. Image credit: Chandra X-ray. Click to enlarge
This beautiful image shows the supernova remnant IC 443. The area in the box contains what looks like a tiny comet with a tail, but it’s actually a neutron star, moving quickly through the nebula. Neutron stars have been seen moving away from supernova remnants before, but in this case, it’s moving perpendicular. One possibility is that the former star was moving quickly through the galaxy before it exploded. The gas and dust in the nebula have slowed down and drifted away from the neutron star.

The pullout, also a composite with a Chandra X-ray close-up, shows a neutron star that is spewing out a comet-like wake of high-energy particles as it races through space.

Based on an analysis of the swept-back shape of the wake, astronomers deduced that the neutron star known as CXOU J061705.3+222127, or J0617 for short, is moving through the multimillion degree Celsius gas in the remnant. However, this conclusion poses a mystery.

Although there are other examples where neutron stars have been located far away from the center of the supernova remnant, these neutron stars appear to be moving radially away from the center of the remnant. In contrast, the wake of J0617 seems to indicate it is moving almost perpendicularly to that direction.

One possible explanation is that the doomed progenitor star was moving at a high speed before it exploded, so that the explosion site was not at the observed center of the supernova remnant. Fast-moving gusts of gas inside the supernova remnant may have further pushed the pulsar’s wake out of alignment. An analogous situation is observed for comets, where a wind of particles from the Sun pushes the comet tail away from the Sun, out of alignment with the comet’s motion.

If this is what is happening, then observations of the neutron star with Chandra in the next 10 years should show a detectable motion away from the center of the supernova remnant.

Original Source: Chandra X-ray Observatory