Astronomers have been watching a small constellation in the night sky, waiting for a double star system to explode nearby. The wait may finally be over: A numerical estimate predicts that a rare supernova flare could occur on Thursday, March 27.
The T Queen of Borealis (T CrB), also known as the Blazing Star, is a binary star system located 3,000 light-years from Earth. It periodically explodes in a recurring supernova about every 79 years, and is about to erupt.
According to NASA, over the past decade, the Lightning Star has been behaving in the same way as it did on the eve of its last visible outburst almost 80 years ago. The current window for the rare astronomical event opened in February 2024 and remains open. Since last year, astronomy enthusiasts have been keeping a close eye on the sky in anticipation of this star boom. An article published last year in the Scientific Notes of the American Astronomical Society estimated that the star will most likely explode on Thursday, March 27 – so get ready to look up.
When will the Lightning Star explode?
To more accurately determine the date of the next explosion, astronomer Jean Schneider from the Paris Observatory, author of the 2024 study, combined previous explosion dates with the orbital dynamics of the star system. The researcher found that the supernovae outbursts occurred at intervals that were exactly a multiple of the orbital period of the star system, meaning that the explosions occurred after a certain number of orbits that the stars had completed around each other. Instead of relying on the behavior of the star system, the authors of the article assume that T CrB explodes once every 128 orbits, and each orbital period is approximately 227 days.
Based on these calculations, the supernova explosion should occur on March 27. If it doesn’t explode on Thursday, Schneider names the next two dates: November 10, 2025 and June 25, 2026. In his paper, he also predicted August 12, 2024, which we can now obviously rule out. To be clear, Schneider is purely working with numbers; his article does not take into account the physics of how and why an eruption occurs. It’s a one-dimensional approach, so his predictions may not be accurate – but it would be great if the Lightning Supernova erupted according to his extremely strict timetable.
What is the T CrB supernova?
Located in the constellation of Ursa Major, T CrB is a binary system consisting of a white dwarf (the remnants of a dead star with a mass comparable to that of the Sun, squeezed into a body the size of the Earth) and an ancient red giant star. The red giant, whose mass is about 1.12 times that of our Sun, orbits the white dwarf every 227 days. The two stars are separated by only 0.54 AU, which is roughly the distance from the Sun to Venus.
The red giant star is slowly being stripped of hydrogen by the strong gravitational pull of its companion, a white dwarf, as they join in a dangerous orbital dance. The material of the red giant star forms an accretion disk that orbits the white dwarf. When the hydrogen from the red giant star hits the surface of the white dwarf, it causes pressure and heat to build up, eventually triggering a thermonuclear explosion that blows away all that material.
Unlike a supernova, which destroys a dying star, a dwarf star remains intact after a supernova explosion. However, it ejects matter into space in an explosive flash that is bright enough to be seen from Earth with the naked eye. The T CrB supernova was first observed more than 800 years ago, and this cycle repeats on average about once every 79 years.
What you will see in the sky
When the outburst occurs, it will be brief, but will appear as a new star in the sky for just under a week. The star system itself is currently invisible to the naked eye at magnitude +10. However, after the supernova explosion, T CrB will rise to a magnitude of +2, almost as bright as Polaris.
The supernova will be visible in the Northern Hemisphere in the constellation of Polaris, which forms an arcuate shape in the night sky. The supernova explosion will be visible without a telescope for several days after it occurs. Then the star system will start to dim and won’t get brighter for about 80 years, so make sure you catch this rare celestial event.
