This Star Explodes Every 80 Years. And Survives.

Original source (on modern site) | Article images: [1]

NASA's Goddard Space Flight Center

• All stars get a participation trophy for being awesome, but T Coronae Borealis is in a class of its own.
• This locked binary star is pulled into a Saturn-like shape over 80 years before exploding and resetting.
• Its home constellation, Corona Borealis, is the elite special forces of star rarity.

In an age-old bullying dynamic, an enormous red giant star messes with its tiny white dwarf neighbor until the white dwarf has had enough—and explodes. This cycle, which repeats every 80 years, creates a temporarily visible phenomenon as bright as the North Star called a recurring nova. And one is about to happen in our sky.

During a surprise event sometime between now and September, people around the world will see a recurring nova that's one of just 5 in the entire Milky Way, Agence France-Presse reports. It's the result of two stars locked in a binary system, in a constellation area known as Corona Borealis (which means "northern crown" in Latin).

The constellation is an arc of stars that was visible to the naked eye even in the second century CE, and is comprised of seven stars—none of which are T Corona Borealis (TCB). But the star is in that area of the sky, so it's probably the best benchmark to look for if you're searching for TCB. During the star's eruption this year, viewers will see Corona Borealis with an additional bright object nearby.

TCB is a truly rare cataclysmic variable star. These are marked by a tiny white dwarf star—a core of a star that has been stripped of any of its outer matter and become very, very dense—orbiting a larger, typically cooler star. That larger star spews material back onto the white dwarf. Even though the red giant in TCB is much larger that the white dwarf, the dwarf's gravity pulls so hard that it draws in some of the giant's mass.

Over time, this matter forms a Saturn-like appearance between the two stars—it surrounds the red giant star and accumulates on the white dwarf as an accretion disk. And once enough matter accretes, it's time for the climax of the "cataclysm."

A cataclysm can be a sudden disaster, or it can be a longer-term flood. In the case of TCB, it's both. The white dwarf is deluged until it's surrounded by enough matter that it undergoes an extremely hot, bright nuclear reaction—a reaction that takes about 80 years to power up. After the days-long recurring nova, the white dwarf goes back to business as usual.

Both of these stars are technically dying, but that process takes millions or billions of years. In their incredible lifespan, a blip every 80 years is almost nothing. But that doesn't mean it's not incredibly special. There are stars in Corona Borealis that are certainly unusual—there's a binary system with two stars that rotate every 10 years, a star that flashes every 16 minutes, and a supergiant with cycling brightness and whose dust cloud can reach about 2,000 times the distance from Earth to the Sun, to name a few—but they're overshadowed by having TCB (the lottery winner of star rarity) in the same neighborhood.

NASA reports that scientists who monitor TCB are observing similar milestones to those that led up to the star's last eruption in 1946. Once the eruption starts, it will last several days, or longer for those with binoculars or telescopes. So, best keep your eyes peeled. You won't want to miss this one.

Caroline Delbert

Caroline Delbert is a writer, avid reader, and contributing editor at Pop Mech. She's also an enthusiast of just about everything. Her favorite topics include nuclear energy, cosmology, math of everyday things, and the philosophy of it all. 

Watch Next

Advertisement - Continue Reading Below

Advertisement - Continue Reading Below

Advertisement - Continue Reading Below