The Impending Explosion of the Blaze Star: 80 Years in the Making!

The countdown has begun for the binary star T Coronae Borealis, as it’s soon to explode in an eruption of brightness that will be visible from Earth. While astronomers can’t determine the precise moment this event will occur, they anticipate that the binary star — known as the Blaze Star — is likely to ignite sometime in 2025.

The Detonation Cycle of T CrB

T Coronae Borealis (T CrB) is a nova situated approximately 3,000 light-years away from Earth in the constellation Corona Borealis (the Northern Crown), which can be found in the northern expanse of the sky. It consists of a pair of stars that revolve around each other: one is a white dwarf star — the scorching, compact core of a star that remains after a low- or intermediate-mass star has depleted its fuel, nearing its evolutionary end. The other is a red giant, a prior stage of stellar evolution in which a star on its last legs, featuring an expanding radius and reduced surface temperature, exhausts its hydrogen supply.

The relationship between these two stars triggers a violent reaction that significantly enhances the brightness of the star system, albeit for a short duration. As the red giant discards its outer layers, the white dwarf will siphon the hydrogen debris to its own surface. This accumulation of pressure and heat eventually leads the star to a point of crisis, resulting in a thermonuclear explosion.

The phenomenon of this nova is a sight that most individuals on Earth might only witness once in their lifetime. This is due to the fact that T CrB is a recurrent nova, indicating that it undergoes a cycle wherein the white dwarf receives material from its companion star, ignites, and then repeats the cycle (a nova typically does not lead to the destruction of a white dwarf, unlike what occurs in most supernovae).

Read More: Astronomers Will Be Ready To Study Future Supernovas In Action

Eighty Years Awaiting a Nova

The initial discovery of T CrB occurred in 1866 by the Irish astronomer John Birmingham, but it was not until the subsequent nova in 1946 that astronomers understood it only manifests every 80 years. Based on this rhythm, we are currently overdue for another T CrB eruption.

Indicators of an approaching explosion started to arise in 2016 when the star noticeably brightened, and then, in April 2024, a significant drop in brightness was reported by the American Association of Variable Star Observers.

This sequence of events — a brightness surge lasting nearly a decade followed by a sudden pre-eruption reduction — mirrors the lead-up to the previous nova in 1946. With this context, scientists first estimated that the nova would occur between Late Spring and Early Fall 2024. However, the year elapsed and T CrB remained dormant.

The reality is, novae such as T CrB are somewhat erratic and do not follow a strict timeline. The fluctuations in brightness suggest that the nova could transpire at any moment now, yet pinpointing a precise date is impossible. Nevertheless, astronomers are optimistic that it will occur in 2025, and they will continue vigilant observations of the white dwarf near the Corona Borealis constellation for any changes.

Where Will T CrB Be Visible?

From our vantage point on Earth, the nova will create a newly illuminated star appearing in the night sky. However, it will only be observable for a short span of days before it diminishes, so stargazers should be prepared for whenever T CrB chooses to shine.

The star will be visible between the constellations Hercules and Boötes; an alternative method to locate it is by tracing a straight line from Arcturus to Vega, two of the brightest stars in the northern celestial hemisphere. The constellation Corona Borealis lies almost directly in the middle of this imaginary line, and T CrB will shine right adjacent to the constellation.

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Jack Knudson is an assistant editor at Discover with a keen interest in environmental science and history. Before joining Discover in 2023, he pursued journalism at the Scripps College of Communication at Ohio University and previously interned at Recycling Today magazine.