An Astronomer Calculated the Exact Day a Star Will Blow—and It’s This Week (Image Credit: Gizmodo-com)
Astronomers have been watching a small constellation in the night sky, waiting for a nearby binary star system to explode. The wait may finally be over: A numerical estimate predicts the rare nova eruption could happen on Thursday, March 27.
T Coronae Borealis (T CrB), also known as the Blaze Star, is a binary star system located 3,000 light-years from Earth. It periodically explodes in a recurring nova every 79 years or so, and it’s due for an impending eruption.
The Blaze Star has spent the past decade behaving much like it did in the lead-up to its last visible eruption nearly 80 years ago, according to NASA. The current window for the rare astronomical event opened in February 2024 and remains open. Astronomy enthusiasts have been keeping a close eye on the skies since last year, waiting for that stellar boom. A paper published last year in Research Notes of the American Astronomical Society estimated that the star is likely to explode on Thursday, March 27—so get ready to look up.
When will the Blaze Star explode?
To better pinpoint the next eruption date, the astronomer behind the 2024 study, Jean Schneider of the Paris Observatory, combined the previous explosion dates with the orbital dynamics of the star system. The researcher found that the nova eruptions occurred at intervals that were an exact multiple of the star system’s orbital period—meaning the explosions happened after a specific number of orbits the stars completed around each other. Rather than relying on the behavior of the star system, the paper suggests that T CrB explodes once every 128 orbits, with each orbital period being roughly 227 days.
Based on these calculations, the nova is set to take place on March 27. Should it fail to explode on Thursday, Schneider lists two subsequent 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 strictly running the numbers; his paper does not take into account the physics of how or why the eruption happens. It’s a one-dimensional approach, so his predictions could be way off—but wow would that ever be neat if the Blaze Star erupts according to his unusually strict timeline.
What is the T CrB nova?
Located in the Corona Borealis constellation, T CrB is a binary system made up of a white dwarf (the remains of a dead star with a mass comparable to that of the Sun squeezed into an Earth-sized body) and an ancient red giant star. The red giant, roughly 1.12 times the mass of our Sun, orbits the white dwarf every 227 days. The two stars are separated by only 0.54 astronomical units, about the same as the distance from the Sun to Venus.
The red giant star is slowly being stripped of its hydrogen by the strong gravitational pull of its companion, the white dwarf, as the two are interlocked in a dangerous orbital dance. The material from the red giant star forms an accretion disk, which swirls around the white dwarf. As the hydrogen from the red giant star accretes onto the surface of the white dwarf, it causes a buildup of pressure and heat, which eventually triggers a thermonuclear explosion that blasts away all that material.
Unlike a supernova, which destroys a dying star, the dwarf star remains intact after the nova explosion. It does, however, blast the material into space in an explosive flash that’s bright enough to see from Earth with the unaided eye. The first recorded sighting of the T CrB nova was more than 800 years ago, and the cycle repeats itself roughly once every 79 years on average.
What you’ll see in the sky
When it does take place, the outburst will be brief but it will appear as a new star in the sky for a little less than a week. The star system itself is currently invisible to the unaided eye at a magnitude of +10. However, following its nova explosion, T CrB will be elevated to a magnitude of +2, almost as bright as the North Star.
The nova will be visible in the Northern Hemisphere in the Corona Borealis constellation, which forms an arc shape in the night skies. You can spot the stellar explosion without a telescope for several days after it happens. The star system will then begin to dim and won’t brighten again for roughly another 80 years, so make sure you catch this rare celestial event.
