Image Credit: NASA/JPL-Caltech/UCLA/WISE Team
Puppis A is a middle-aged supernova remnant of about 10 light-years in diameter, located some 7,000 light-years away in our Milky Way, in the constellation of Puppis. The supernova explosion took place — and would have been seen on Earth as a new bright star in the sky — approximately 3700 years ago, but was eventually forgotten until modern astronomers found it again in October 1971.
A supernova occurs when a star explodes in the final phase of its life. The exploding star can become billions of times as bright as the Sun before gradually fading from view. At its maximum brightness, the exploded star may outshine an entire galaxy.
After some supernova explosions, when a star collapses and becomes so dense that protons and electrons squish together to form neutrons, there remains a small, ultra-dense neutron star. (After other supernova explosions, a black hole may be left behind.) The explosion throws a large, roughly spherical cloud of dust and hot gas into space surrounding the neutron star (or black hole). When this slams into the existing interstellar medium, it heats up so much it glows in X-rays.
Supernova explosions are enriching the intergalactic gas with elements like oxygen, iron, and silicon that will be incorporated into new generations of stars and planets.
The massive star that formed Puppis A ended its life in an extremely bright and powerful explosion. The expanding shock waves from that explosion are heating up the dust and gas clouds surrounding the supernova, causing them to glow and creating the red cloud we see here. Much of the material from that original star was violently thrown out into space.
However, in the center of the red cloud remained a neutron star (too faint to be seen in this image). This hypervelocity neutron star, called the Cosmic Cannonball (also known as RX J0822-4300), is currently moving away from the center of the supernova remnant at approximately 5.4 million kilometers per hour (1,500 kilometers per second), making it one of the fastest moving stars ever found.
Some of the green-colored gas and dust in the image is from yet another ancient supernova — the Vela supernova remnant. Although Puppis A overlaps the Vela Supernova Remnant, it is four times more distant. Puppis A is one of the brightest X-ray sources in the X-ray sky. Its X-ray designation is 2U 0821-42.
This image was made from observations by all four infrared detectors aboard NASA’s Wide-field Infrared Survey Explorer (WISE). Blue and cyan (blue-green) represent infrared light which is primarily from stars, the hottest objects pictured. Green and red represent light which is primarily from warm dust.