In what is being called a “once-in-a-lifetime event,” light from a thermonuclear explosion on a star has been traveling to Earth for thousands of years and will be here any day.
T Coronae Borealis (also known as T Cor Bor, T CrB and the Blaze Star) will be as bright as the North Star (for those in the northern hemisphere).
Dr Laura Driessen, from the University of Sydney’s school of physics, said the Blaze Star would be as bright as Orion’s right foot for those in the southern hemisphere.
A recurring nova, T CrB becomes visible about every 80 years after a thermonuclear explosion on the surface of a white dwarf about 3,000 light-years away.
The dwarf sucks up hydrogen from a neighboring red giant, and this causes a build-up of pressure and heat that eventually causes the explosion.
Known as a nova (for “new”), it is expected to become visible anytime between now and September.
In the Corona Borealis there is a dark spot. Astronomers and non-astronomers everywhere are monitoring that spot, which is where the “new” star will appear. It will remain visible to the naked eye for about a week.
Nasa called it a “once-in-a-lifetime event”.
Driessen said the two stars are close enough that a gravitational pull causes the white dwarf to suck in material.
“It’s a binary system and every now and then it has an eruption, so it’s a nova,” she said.
“When we think nova, we often think supernova, that’s when they explode at the end of their life… there’s no coming back from that. But a nova has smaller surface explosion, based on this accretion, this collection of material.”
The first recorded sighting of the Blaze Star was in 1217, when the abbot of Ursberg, in Germany, “saw a dim star which for a time shone with great light”. Nasa says.
It was last seen in 1946.
Driessen said the star is always changing, getting brighter and dimmer. But about 10 years before an explosion, it starts to brighten a bit, before fading again in the months before the explosion.
“It’s not really going to be like clockwork, it has to do with building up material. So it’s not an exact number, but we have this early warning,” she said.
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While the spectacular phenomenon has been observed before, Driessen said this is the first time it will be studied with modern technology.
“That’s why it’s so exciting. It will be the first one where we get the information that we have access to now, we have all these telescopes that we didn’t have 80 years ago,” she said.
Nasa’s Fermi Gamma-ray Space Telescope, the James Webb Space Telescope and the National Radio Astronomy Observatory’s Very Large Array in New Mexico are just a few of the instruments that will follow the Blaze.
Fermi Project Scientist Dr. Elizabeth Hays, who is also head of Nasa’s Astroparticle Physics Laboratory, said typical nova events were far away.
“This one will be very close, with many eyes on it, studying the different wavelengths and hopefully giving us data to start unlocking the structure and specific processes involved,” she said.
“We can’t wait to get the full picture of what’s going on.”
Nasa has a map of the Corona Borealis to help people determine where to look, and Driessen said software like Stellarium is also helpful. There are several free apps for viewing maps of the night sky.
Driessen said people should find the darkest area they can, as far away from a city or town as possible, and take binoculars for an even better view.
“Let your eyes adjust to the dark,” she said. “And it’s good to have a red torch. Throw some cellophane over it so it doesn’t ruin your night vision. And don’t look at your phone.”
