Ashes to ashes, dust to dust

A new image from NASA’s Chandra and Spitzer space telescopes shows the dusty remains of a collapsed star. The dust is flying past and
engulfing a nearby family of stars.

“Scientists think the stars in the image are part of a stellar cluster in which the supernova exploded,” said Tea Temim of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts. “The material ejected in the explosion is now blowing past these stars at high velocities.”

The composite image of G54.1+0.3 shows the Chandra X-ray Observatory image in blue, and data from the Spitzer Space Telescope in green (shorter wavelength) and red-yellow (longer). The white source near the center of the image is a dense, rapidly rotating neutron star, or pulsar, left behind after a core-collapse supernova explosion. The pulsar generates a wind of high-energy particles — seen in the Chandra data — that expands into the surrounding environment, illuminating the material ejected in the supernova explosion.

The infrared shell that surrounds the pulsar wind is made up of gas and dust that condensed out of debris from the supernova. As the cold dust expands into the surroundings, it is heated and lit up by the stars in the cluster so that it is observable in the infrared. The dust closest to the stars is the hottest and is seen to glow yellow in the image. Some of the dust is also being heated by the expanding pulsar wind as it overtakes the material in the shell.

The unique environment into which this supernova exploded makes it possible for astronomers to observe the condensed dust from the supernova that is usually too cold to emit in the infrared. Without the presence of the stellar cluster, it would not be possible to observe this dust until it becomes energized and heated by a shock wave from the supernova. However, the very action of such shock heating would destroy many of the smaller dust particles. In G54.1+0.3, astronomers are observing pristine dust before any such destruction.

G54.1+0.3 provides an exciting opportunity for astronomers to study the freshly formed supernova dust before it becomes altered and destroyed by shocks. The nature and quantity of dust produced in supernova explosions is a long-standing mystery, and G54.1+0.3 supplies an important piece to the puzzle.