An international team of astronomers may have discovered the biggest and brightest supernova ever.
The explosion was 570 billion times brighter than the sun and 20 times brighter than all the stars in the Milky Way galaxy combined, according to a statement from The Ohio State University, which is leading the study. Scientists are straining to define its strength.
“This may be the most powerful supernova ever seen by anybody … it’s really pushing the envelope on what is possible,” study co-author Krzysztof Stanek, an astronomer at Ohio State, was quoted as saying in The Los Angeles Times.
The team of astronomers released their findings this week in the journal Science. The explosion and a gas cloud that resulted are called ASASSN-15lh after the team of astronomers, All Sky Automated Survey for Supernovae, that discovered it last June.
A supernova is a rare and often dramatic phenomenon that involves the explosion of most of the material within a star. Supernovas can be very bright for a short time and usually release huge amounts of energy.
Searching for the power source
This blast created a massive ball of hot gas that the astronomers are studying through telescopes around the world, Ohio State said. It cannot be seen with the naked eye because it is 3.8 billion light-years from Earth.
There’s an object about 10 miles across in the middle of the ball of gas that astronomers are trying to define.
“The honest answer is at this point that we do not know what could be the power source for ASASSN-15lh,” said Subo Dong, lead author of the Science paper, according to Ohio State. He is a Youth Qianren Research Professor of astronomy at the Kavli Institute for Astronomy and Astrophysics at Peking University.
Todd Thompson, professor of astronomy at Ohio State, said the object in the center may be a rare type of star called a millisecond magnetar. Spawned by a supernova, it’s a rapidly spinning, dense star with a powerful magnetic field.
Could it be a ‘supermassive black hole’?
To achieve the brightness recorded, the magnetar would have to spin 1,000 times a second and “convert all that rotational energy to light with nearly 100 percent efficiency,” Thompson said, according to the Ohio State press release. “It would be the most extreme example of a magnetar that scientists believe to be physically possible.”
The question of whether a supernova truly caused the space explosion may be settled later this year with help from the Hubble Space Telescope, which will allow astronomers to see the host galaxy surrounding the object in the center of the ball of gas, Ohio State said.
If it’s not a magnetar, it may be unusual nuclear activity around “a supermassive black hole,” Ohio State said.