'Once-in-a-lifetime' star system explosion could be visible from Earth: How to see it

There is now one more reason to gaze at the sky, total solar eclipse aside. 

The explosion of a distant “star system” will temporarily paint the night sky with its bright guts soon, offering stargazers the opportunity to witness a truly mesmerizing moment, NASA said in late February. 

T Coronae Borealis, or T CrB’s “nova outburst” has the potential to be a “once-in-a-lifetime” occasion, as the celestial event only occurs once every 80 years. 

This star system “last exploded in 1946 and astronomers believe it will do so again between February and September 2024,” according to NASA. 

Here’s what we know.

Nova outburst won’t give much warning, happens unexpectedly 

It is difficult to predict when T Coronae Borealis, a binary system with a white dwarf (dead stars) and red giant (aging stars) will erupt, only doing so when the red giant becomes “unstable from its increasing temperature and pressure,” according to NASA.

The red giant begins to shed its outer layers, which are subsequently collected by the white dwarf, placing the matter onto its surface. 

“The shallow dense atmosphere of the white dwarf eventually heats enough to cause a runaway thermonuclear reaction – which produces the nova we see from Earth,” NASA says. 

William J. Cooke, lead of NASA’s Meteoroid Environment Office, told CNN that most novae (extremely bright white dwarf stars) happen unexpectedly, without warning. 

“However, T Coronae Borealis is one of 10 recurring novae in the galaxy. We know from the last eruption back in 1946 that the star will get dimmer for just over a year before rapidly increasing in brightness,” Cooke said. 

Some researchers are expecting T Coronae Borealis “to go nova” between now and September because the star system began to in March of last year. 

“But the uncertainty as to when this will happen is several months – can’t do better than that with what we know now,” according to Cooke. 

Astronomers estimate that between 20 and 50 novae occur each year in our galaxy, but despite their power most go undiscovered, NASA wrote in 2014. 

Keep your eyes on the night sky, NASA’s social media page for updates

T Coronae Borealis, located 3,000 light-years away from Earth, is just a little too dim and far to be observed by the “unaided eye” (without a powerful telescope).

But this “nova outburst” will give stargazers the rare chance to witness a brightness akin to the North Star, also known as Polaris. 

“Once its brightness peaks, it should be visible to the unaided eye for several days and just over a week with binoculars before it dims again, possibly for another 80 years,” according to NASA. 

Astronomers will witness the nova by way of Hubble Space Telescope, studying the celestial event through X-ray and ultraviolet light using the space-based Neil Gehrels Swift Observatory, CNN reported. 

“Studying recurring novae like T Coronae Borealis help us understand the mass transfer between the stars in these systems and provide insights into the thermonuclear runaway that occurs on the surface of the white dwarf when the star goes nova,” Cooke shared with CNN. 

Cooke, who witnessed the Nova Cygni back in 1975, will never forget the moment he witness the celestial glow for the first time. 

“I was a teenage astronomy geek about to start college and was outside on the night of Aug. 29. Glancing at the sky, I noticed that the constellation of Cygnus was messed up; there was a star that shouldn’t be there. After enduring some comments from friends who thought I was crazy, I got them to look and we realized that we were looking at a nova!" Cooke told CNN.

He says that the moment “reinforced my choice of astronomy as a career. I used to joke that a star had to explode in order to get me to suffer through undergraduate physics," Cooke told CNN.

It's unlikely that Nova Cygni will erupt again, but the brightness is expected to be similar to T Coronae Borealis, CNN reported.

NASA recommends stargazers to  “become familiar with the constellation Corona Borealis, or the Northern Crown – a small, semicircular arc near Bootes and Hercules, which is where the outburst will appear as a “new” bright star.

Updates about T Coronae Borealis can be found @NASAUniverse on X, formerly known as Twitter.