Explosive stellar event will create unique vision in the sky; understand

Astronomers expect a “new star” to appear in the night sky any time between now and September, and it promises to be a unique celestial sight, according to NASA.

The expected bright event, known as a nova, will occur in the constellation of Corona Borealis, or Northern Corona, of the Milky Way which is located between the constellations of Boötes and Hercules.

While a supernova is the explosive death of a massive star , a nova refers to the sudden, brief explosion of a collapsed star known as a white dwarf .

T Coronae Borealis, also known as the “Flame Star,” is a binary system in Corona Borealis that includes a dead white dwarf star and an aging red giant star. Red giants form when stars exhaust their supply of hydrogen for nuclear fusion and begin to die. In about 5 billion or 6 billion years, our sun will become a red giant, inflating and expanding as it sheds layers of material and likely evaporating the Solar System's inner planets, although Earth's fate remains uncertain, according to to NASA.

Every 79 years or so, T Coronae Borealis experiences an explosive event.

The stars in the orbiting pair are close enough to each other to interact violently. The red giant becomes increasingly unstable over time as it heats up, shedding its outer layers that fall as matter onto the white dwarf star.

The exchange of matter causes the white dwarf's atmosphere to gradually heat up until it experiences a “runaway thermonuclear reaction,” resulting in a nova, as seen in the animation below, according to the space agency.

Keeping an eye on the changing sky

T Coronae Borealis experienced its last explosive flare-up in 1946, and astronomers are keeping a close eye on the star system once again.

“Most novae happen unexpectedly, without warning,” said William J. Cooke, leader of NASA's Office of Meteoroid Environments, in an email. “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 be dimmer for just over a year before rapidly increasing in brightness. T Coronae Borealis began weakening in March last year, so some researchers expect it to explode between now and September. But the uncertainty about when that will happen is several months away – we can’t do better than that with what we know now.”

O star system, located 3,000 light years from Earth and generally too faint to be seen with the naked eye should reach a brightness level similar to that of Polaris, or that of the North Star.

Once the nova reaches peak brightness, it will be as if a new star has appeared – one that is visible for a few days without any equipment and a little over a week with binoculars before dimming and disappearing from view for another 80 years. or something like that.

The nova will appear in a small arc between the constellations Boötes and Hercules, and will be visible from the Northern Hemisphere .

Astronomers will observe the nova using the Hubble Space Telescope and will study the celestial event using ultraviolet light and X-rays using the Neil Gehrels Swift Space Observatory.

“Studying recurring novae like T Coronae Borealis helps us understand mass transfer between stars in these systems and provides insights into the runaway thermonuclear reaction that occurs on the surface of the white dwarf when the star explodes into a nova,” said Cooke.

The NASAUniverse account on X, formerly known as Twitter, will provide updates on the outbreak and what it looks like.

Cooke recalled that the last nova he witnessed – Nova Cygni in 1975 – had a brightness similar to what one would expect from T Coronae Borealis. Nova Cygni is not expected to experience another explosion again.

“I was a teenage astronomy geek about to start college and I was outside on the night of August 29th,” Cooke said. “Looking up at the sky, I noticed that the Cygnus constellation was messed up; there was a star that shouldn't be there. After enduring some comments from friends who thought I was crazy, I managed to get them to look and we realized we were looking at a new one! 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 pass me off as a university physicist.”