If you keep a close eye on the night sky in the coming weeks and months, you might spot something new. It will shine as brightly as Polaris, the North Star, for no more than a week before fading back into darkness.
This ephemeral beacon is T Coronae Borealis, often referred to as T CrB. It’s news, a nuclear explosion erupting from the pale corpse of a long-dead star. Some people may have seen it before – the same mesmerizing sight lit up our skies almost 80 years ago – and future generations may see it in another 80 years.
For any world nearby, a nova would be revealing. But for astrologers on our world, some 3,000 light-years away, “it’s a fun and exciting coming cataclysm,” he said. Bradley Shafferan astrophysicist at Louisiana State University.
Here’s everything you need to know about this event: what it is, when it’s happening, and where you can see it.
What is nova?
There are more than 400 known novae in the Milky Way galaxy. They result from the explosive pairing between a normal type of star—for example, a main-sequence furnace like Earth’s sun or an elephantine red giant—and a smoldering white dwarf stellar core left behind after the demise of a star. Both are gravitationally bound companions destined to unleash a fiery explosion on the world.
White dwarfs are relatively small, but they are also so dense that their strong gravitational pulls steal hydrogen-rich matter from a nearby normal star. This volatile material falls to the surface of the white dwarf and begins to accumulate after a while, crushing the lower layers and raising their temperature.
Eventually, this compressed matter “exceeds the ignition temperature of hydrogen,” Dr. Schaefer said. It ignites, raising the temperature of the accumulated material even more. After a certain point, an unexpected nuclear reaction begins, setting off an apocalyptic explosion.
“These youngsters are basically hydrogen bombs,” Dr. Schaefer said.
But don’t confuse a nova with its more violent sibling, the supernova, which permanently destroys a star and angrily throws off its outer layers. After a nova’s nuclear embers die down, the cycle begins anew, with the white dwarf once again on its way to another explosion.
What is T Coronae Borealis and how do we know when it will explode?
T CrB is a nova that results when a white dwarf peels off enough of the outer layers of a red giant star that is about 74 times the size of our sun.
The nova last exploded in 1946. Astronomers also observed it exploding in 1866, and historical references show that it was located in 1787 and 1217.
Most novae have explosive cycles that last many millennia. But T CrB is impatient—a voracious consumer of its red giant’s stellar fuel. Previous observations show that it erupts once every 80 years, making it a recurring nova – one that flares up at least once a century.
Previous observations by T CrB have also shown that nova burn and break up in a particularly erratic way in the years before an explosion, and things appear to be no different this time: activity in the last decade roughly suggests that it is preparing for an imminent eruption, one that will take place anytime between now and September.
Where in the night sky will I be able to see it?
T CrB will appear in the constellation Corona Borealis, which borders Hercules and Botes. When he ‘blows his stack, it will be as bright as the north STAR and will be visible for a few days,” said Bill Cook, chief of the Meteor Environment Office at NASA’s Marshall Space Flight Center in Huntsville, Ala.
“You will notice a new star in the sky,” he added, visible to the naked eye.
Do not miss it. “It’s a once-in-a-lifetime phenomenon,” Dr. Cook said. “How often can people say they’ve seen a star explode?”