Skywatchers: A once in a lifetime cosmic event, NASA says this summer

A conceptual image of how to find Hercules and the “Northern Crown” in the night sky, created using planetarium software. Look up after sunset during summer months to find Hercules, then scan between Vega and Arcturus, where the distinct pattern of Corona Borealis may be identified.

NASA

Heads up sky gazers, this summer, a rare once in a lifetime event is anticipated to occur, resulting in professional and amateur astronomers alike becoming fixated on on one small constellation deep in the night sky.

“It’s a once-in-a-lifetime event that will create a lot of new astronomers out there, giving young people a cosmic event they can observe for themselves, ask their own questions, and collect their own data,” said Rebekah Hounsell, an assistant research scientist specializing in nova events at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “It’ll fuel the next generation of scientists.”

Located among the seven stars of Corona Borealis, within the “Northern Crown,” the rare event is a dark spot where an impending nova will occur—so bright it will be visible on Earth with the naked eye, NASA says. Known as the T Coronae Borealis, dubbed the “Blaze Star” and known to astronomers simply as “T CrB,” it is a binary system nestled in the Northern Crown approximately 3,000 light-years from Earth.

A red giant star and white dwarf orbit each other in this animation of a nova similar to T Coronae Borealis. The red giant is a large sphere in shades of red, orange, and white, with the side facing the white dwarf the lightest shades. The white dwarf is hidden in a bright glow of white and yellows, which represent an accretion disk around the star. A stream of material, shown as a diffuse cloud of red, flows from the red giant to the white dwarf. When the red giant moves behind the white dwarf, a nova explosion on the white dwarf ignites, creating a ball of ejected nova material shown in pale orange. After the fog of material clears, a small white spot remains, indicating that the white dwarf has survived the explosion.

NASA/Goddard Space Flight Center

The system is described as an Earth-sized remnant of a dead star with a mass comparable to that of (our) sun called a white dwarf.

“An ancient red giant slowly being stripped of hydrogen by the relentless gravitational pull of its hungry neighbor,” NASA said. “The hydrogen from the red giant accretes on the surface of the white dwarf, causing a buildup of pressure and heat. Eventually, it triggers a thermonuclear explosion big enough to blast away that accreted material. For T CrB, that event appears to reoccur, on average, every 80 years.”

The last time the T CrB nova was seen from Earth was in 1946, and the first record of it was more than 800 years ago. “In the autumn of 1217, Burchard, abbot of Ursberg, Germany, noted his observance of ‘a faint star that for a time shone with great light.’

A nova differs from a supernova, which is an explosion that destroys dying stars, NASA explains. During a nova event, the dwarf star remains intact and sends accumulated material hurtling into space in a blinding flash. The nova cycle typically repeats itself over time as a process that can carry on for thousands of years.

“There are a few recurrent novae with very short cycles, but typically, we don’t often see a repeated outburst in a human lifetime, and rarely one so relatively close to our own system,” Hounsell said. “It’s incredibly exciting to have this front-row seat.”

Researchers say if the current T CrB nova pattern continues, the nova event could occur by September 2024. When the event occurs, the outburst will be brief. However, once it erupts, it will be visible to the naked eye for a little less than a week. “I’m confident it will be quite a sight,” Hounsell added.