For the first time, astronomers have quantified the movements of an extraordinary cosmic structure using the Chandra X-ray Observatory of NASA.
The team observed the blast wave and debris, produced by an exploded star, traveling away from the site of the explosion and striking a surrounding gas wall.
According to the astronomers, the light produced from the supernova explosion reached planet Earth around 1,700 years ago, or when the Jin dynasty ruled China and the Mayan empire was thriving.
But by cosmic principles, the supernova remnant created by the explosion, known as MSH 15-52, is one of the youngest in the Milky Way galaxy. The supernova explosion also produced an extremely dense, magnetized star known as a pulsar, which subsequently discharged a bubble of energetic particles — that is, an X-ray-emitting nebula.
Since the time of this explosion, the supernova remnant — which is composed of debris from the disintegrated star and also the blast wave of the explosion — and the X-ray nebula have been altering as they expand outward into space. More importantly, the X-ray nebula and the supernova remnant currently look like the shape of a palm and fingers.
In the past, astronomers have launched a full Chandra view of the “hand,” as illustrated in the above image. Now, new research work has reported how rapidly the hand-associated supernova remnant is moving, as it collides with a cloud of gas known as RCW 89. The internal edge of this cloud creates a gas wall situated around 35 light-years from the explosion core.
To follow up the movement, the researchers used Chandra data from 2004 to 2008, and subsequently an integrated image from observations taken in late 2017 and early 2018. All three epochs are shown in the inset of the above graphic.
The rectangle, which is fixed in space, emphasizes the movement of the blast wave caused by the explosion, which is situated close to one of the fingertips. This feature is traveling at nearly 9 million miles per hour. The fixed squares surround the clumps of neon and magnesium that probably formed in the star before exploding and shooting into space after the star exploded.
Part of this explosion debris is traveling at an even greater speed of over 11 million miles every hour. A color version of the image captured in 2018 shows the clumps of neon and magnesium in yellow and red and the fingers in green and blue.
Although these are unexpectedly high speeds, they truly represent a deceleration of the supernova remnant. Scientists have predicted that to reach the farthest RCW 89 edge, the material would need to move, on average, at nearly 30 million miles every hour. This prediction is based on the distance between the core of the explosion and RCW 89 and the age of the supernova remnant.
This speed difference suggests that the material has traveled via a low-density cavity of gas and was later considerably slowed down by running into RCW 89.
The exploded star probably lost part or all of its external layer of hydrogen gas in a wind and created such a cavity, before exploding, the same way as the star that burst to form the popular supernova remnant, called Cassiopeia A (Cas A) — relatively younger at an age of around 350 years.
Around 30% of giant stars that disintegrate to create supernovas are of the same type. The clumps of debris observed in the 1,700-year-old supernova remnant might be older models of those observed in Cas A at optical wavelengths with respect to their initial densities and speeds.
This implies that both these objects probably have the same fundamental source for their explosions, which is more or less associated with how stars with stripped layers of hydrogen explode. Astronomers, however, are still unsure about the details and will continue to explore this possibility.
An article explaining these findings was published in the June 1st, 2020, issue of The Astrophysical Journal Letters, with a preprint available online. The study authors are Kazimierz Borkowski, Stephen Reynolds and William Miltich, all from North Carolina State University located in Raleigh.
NASA’s Marshall Space Flight Center handles the Chandra program. The Chandra X-ray Center of the Smithsonian Astrophysical Observatory manages science from Cambridge Massachusetts and flight operations from Burlington in Massachusetts.
Quick Look: Cosmic Hand Hitting a Wall
Video Credit: Harvard-Smithsonian Center for Astrophysics.
Borkowski, K. J., et al. (2021) Fast Blast Wave and Ejecta in the Young Core-collapse Supernova Remnant MSH 15-52/RCW 89. Astrophysical Journal Letters. doi.org/10.3847/2041-8213/ab91c0.