Listen to the UVA Today Radio Show report on this story by Fariss Samarrai:
June 15, 2011 — In 1987, astronomers observed the closest supernova explosion witnessed in nearly 400 years. They dubbed it Supernova1987A, and they've been eyeing its changes ever since, using the Hubble Space Telescope and Earth-based observatories to gain a nearly pristine view of what happens when a star dies.
"A supernova is an exploding star and it acts like a big bomb when it goes off," said astronomer Roger Chevalier of the University of Virginia's College of Arts & Sciences, co-author of a new study detailing recent observations of Supernova1987A published in the June 8 edition of the journal Nature.
The dying star, located 170,000 light years away in our neighboring galaxy, the Large Magellanic Cloud, is rapidly evolving, allowing astronomers a continuing opportunity to see what happens as a supernova transitions into a supernova remnant. It may be dying, but it looks anything but dead as it rapidly undergoes changes – to the continuing excitement of observing astronomers.
When a star dies, its inner layers collapse inward, which triggers an explosion and ejects material into space – hydrogen, helium, nitrogen and other elements. Understanding the explosions of dying stars is important to better understand the evolution of the universe, because dying stars provide the material for star and planet formation, and the energy for gas in galaxies.
What Chevalier and his colleagues recently observed is that SN1987A has begun glowing brighter as it becomes a supernova remnant. The increasing brightness is a result of interactions between the exploded material and the surrounding gas. X-rays from surrounding material are illuminating debris from the supernova and heating is making it glow brighter.
Because of the relatively close proximity of SN1987A, and the fact that the Hubble Space Telescope was launched in 1990, not long after its discovery, astronomers are able to observe this supernova in spectacular detail as it evolves on a very short time-scale. They are using it as a living lab for developing and testing theories on the deaths of stars, and, ultimately, how the universe repopulates with stars and, eventually, more planets.
"We can learn about the evolution of the universe, what kinds of stars were exploding when the universe was very young, how those elements got spread around the universe and what's been happening since then," Chevalier said.
"This whole process is very important for the life cycle within the universe, making stars, making planets, leading to life eventually, the kind of elements that are critical for life are in fact produced in these explosions."