Awaiting The Blaze: A New Star Set To Light Up The Night Sky

Astronomers are eagerly anticipating the appearance of a "new star" in the night sky, expected to occur anytime between now and September. This celestial event, which has been years in the making, is set to dazzle stargazers around the world, according to NASA.

“This is a once-in-a-lifetime event that will inspire many new astronomers. It gives young people a cosmic phenomenon they can observe firsthand, ask their own questions about, and collect their own data,” said Dr. Rebekah Hounsell, an assistant research scientist specializing in nova events at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “It will fuel the next generation of scientists.”

The anticipated brightening event, known as a nova, will occur in the Milky Way’s Corona Borealis, or Northern Crown constellation, situated between the Boötes and Hercules constellations.

While a supernova marks the explosive death of a massive star, a nova refers to a sudden, brief explosion from a collapsed star known as a white dwarf. This dwarf star remains intact, releasing material in a repetitive cycle that can last for thousands of years.

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

T Coronae Borealis, also known as the “Blaze Star,” is a binary system in the Corona Borealis consisting of a white dwarf star and an aging red giant star. Red giants form when stars exhaust their hydrogen supply for nuclear fusion and begin to die. In about 5 billion or 6 billion years, our sun will become a red giant, expanding and potentially evaporating the inner planets of our solar system, although Earth’s fate remains uncertain, according to NASA.

Every 80 years or so, T Coronae Borealis experiences an explosive event. The stars in this binary system interact violently as they orbit each other. The red giant, becoming increasingly unstable, sheds its outer layers, which land on the white dwarf star. This matter exchange causes the white dwarf’s atmosphere to heat up until it undergoes a "runaway thermonuclear reaction," resulting in a nova.

A nova from T Coronae Borealis was first recorded in the fall of 1217 by Burchard, abbot of Ursberg, Germany, who noted a “faint star that for a time shone with great light,” according to NASA. The last explosive outburst was in 1946, and astronomers are once again closely monitoring the star system.

“Most novae happen unexpectedly, without warning,” said William J. Cooke, head of NASA’s Meteoroid Environments Office. “However, T Coronae Borealis is one of 10 recurring novae in the galaxy. We know from the last eruption in 1946 that the star will dim for just over a year before rapidly brightening. T Coronae Borealis began to dim in March last year, so some researchers expect it to go nova between now and September. But the timing is uncertain, with a window of several months.”

Located 3,000 light-years from Earth and typically too dim to be seen with the naked eye, T Coronae Borealis is expected to brighten to a level similar to that of Polaris, the North Star. When the nova peaks in brightness, it will appear as if a new star has emerged, visible for a few days without any equipment and for over a week with binoculars, before dimming and disappearing from sight for another 80 years or so.

The nova will be visible in a small arc between the Boötes and Hercules constellations from the Northern Hemisphere. “The Northern Crown is a horseshoe-shaped curve of stars west of the Hercules constellation, ideally spotted on clear nights,” NASA explained. “It can be identified by locating the two brightest stars in the Northern Hemisphere — Arcturus and Vega — and drawing a straight line from one to the other, which will lead skywatchers to Hercules and the Corona Borealis.”

Dr. Elizabeth Hays, chief of the Astroparticle Physics Laboratory at NASA Goddard, highlighted the excitement for amateur astronomers. “Citizen scientists and space enthusiasts are always looking for those strong, bright signals that identify nova events and other phenomena. Using social media and email, they’ll send out instant alerts, and the flag goes up. We’re counting on that global community interaction again with T CrB.”

Astronomers will observe the nova using various ground- and space-based telescopes. Data from citizen scientists could help astronomers understand the events leading up to the eruption, Hounsell said. Typically, nova events are so distant and faint that it’s difficult to get a full picture of the eruption, but “this one will be really close, with a lot of eyes on it,” Hays noted.

“Studying recurring novae like T Coronae Borealis helps us understand the mass transfer between the stars in these systems and provides insights into the thermonuclear runaway that occurs on the white dwarf’s surface when the star goes nova,” Cooke explained.

Cooke reminisced about the last nova he witnessed — Nova Cygni in 1975 — which had a similar brightness to what is expected from T Coronae Borealis. “I was a teenage astronomy geek about to start college and was outside on the night of August 29,” he recalled. “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! It was a very memorable experience and reinforced my choice of astronomy as a career. I used to joke that a star had to explode to get me to suffer through undergraduate physics.”

While it’s possible that T Coronae Borealis won’t explode by September, astronomers are monitoring it closely. “Recurrent novae are unpredictable and contrarian,” said Dr. Koji Mukai, an astrophysics researcher at NASA Goddard. “When you think they follow a certain pattern, they do — and as soon as you rely on them repeating the same pattern, they deviate completely. We’ll see how T CrB behaves.”