© Loretta Dunne, University of Nottingham
A multi-colour image of the Cassiopeia A supernova remnant.
A team of astronomers, led by Loretta Dunne from the University of Nottingham, have found some very unusual stardust. In a paper to be published in
Monthly Notices of the Royal Astronomical Society, Dr Dunne and her team find new evidence for the production of copious quantities of dust in the Cassiopeia A supernova remnant, the remains of a star that exploded about 300 years ago.
Interstellar dust is found throughout the cosmos. It is responsible for the dark patches seen in the Milky Way on a moonless night. It consists of carbon and silicate particles, about the size of those in cigarette smoke. The dust helps stars like the Sun to form and subsequently coagulates to form planets like Earth, and the cores of giant gas planets like Jupiter. It is found in great quantities in galaxies, even very early in the history of the Universe.
The origin of all this dust is, however, a mystery. Does it condense like snowflakes in the winds of red giant stars or is it produced in supernovae - the violent death-throes of massive stars? Supernovae are a good way to produce dust in a blink of the cosmic eye, as massive stars evolve relatively quickly, taking a few million years to reach their supernova stage. In contrast lower-mass stars like our Sun take billions of years to reach their dust-forming red giant phase. Despite many decades of research, astronomers have still not found conclusive evidence that supernovae can produce dust in the quantities required to account for the dust they see in the early Universe.
