If you’ve got a decent pair of binoculars and clear skies, you’ll have a good view Wednesday night of the closest and brightest supernova display of the past 25 years.
The supernova, named SN 2011fe, is the 136th seen by astronomers this year, but its proximity makes it significant not only for stargazers but to the scientific community.
The event was first observed on Aug. 24, only hours after it first became visible from Earth. Located within the Pinwheel Galaxy, the explosion happened 21 million light-years away – a relatively small distance by astronomical standards.
On the scale of astronomical magnitude, in which brighter objects have lower numbers, it was a 17.2 – about 1 million times too dim to be seen by the naked eye.
Since then, “the supernova of a generation,” has been brightening by the minute and will hit its peak this week, said Joshua Bloom, assistant professor of astronomy at the University of California, Berkeley, in a press release.
By Friday, the supernova could hit magnitude 10, still below the 6.5-magnitude threshold to be seen with the naked eye, but visible with binoculars.
The supernova was a Type Ia event, which means a white dwarf star began to siphon material from a nearby star until it became so massive that it exploded. These types of supernovae, in particular, are important to scientists because they are immensely bright, and so act as cosmic mile markers, helping astronomers calculate distances in space and the expansion of the universe.
Its relative nearness to Earth makes SN 2011fe doubly important. Its discoverers have predicted the supernova could become one of the most-studied in history.
The last Type Ia supernova that occurred this close was in 1986, but it was obscured by dust, said Peter Nugent, an astrophysicist at the the Lawrence Berkeley National Laboratory and a member of the team that located the event, in the press release.
The last supernova that could be so well observed was in 1972. That occurred in the NGC 5253 galaxy and reached a magnitude of 8.5.
By contrast, the last known supernovae within our galaxy, the Milky Way, were seen centuries ago, dating to 1604, 1572, and 1054. These objects were visible to the naked eye, with the most recent, known as Kepler's Supernova, reaching a magnitude of minus 2.5, meaning it was visible even in daytime.
SN 2011fe is located in the constellation Ursa Major, better known as the Big Dipper. "The easiest way to find it is to take the last two stars in the handle of the Big Dipper, form an equilateral triangle heading north and bang, you’ll find the Pinwheel Galaxy,” said Nugent.
He said a pair of 80 mm binoculars would suffice to view the display, but a telescope with a lens measuring greater than three inches would be better.
The supernova will begin to fade by the end of the week.