The Flaming Star event first recorded in a medieval manuscript to return

An astronomical anomaly first observed and recorded more than eight centuries ago is about to revisit Earth’s night sky. Sometime between now and September, the double star known collectively as T Coronae Borealis will flare up and make its presence known around the planet, shining at a low intensity that matches the polar star, Polaris. A newly visible star can be visible for up to a week before it dims and disappears into the sky again.

Despite being located approximately 3,000 light-years from Earth, this variable stellar body (dubbed the ‘Blaze Star’) will be visible from many locations, emerging like a beacon in a previously empty patch of sky within the elusive constellation Corona Borealis, not far from more visible constellations Boötes and Hercules. This phenomenon will be the result of a violent interaction between the two stars that make up this binary system, which will generate a flash of light so intense that it will radiate across the Milky Way galaxy undiminished for the equivalent of several Earth days.

Will see ‘Wonderful Sign’

The first recorded sighting of T Coronae Borealis (T CrB) occurred in 1217, when a German monk known as Abbott Burchard described the appearance of a brightening point of light within the confines of the Corona Borealis.

“A wonderful sign was seen,” he noted in a medieval manuscript, in the form of an object that “shined with a great light” for “many days.”

While Abbott was once believed to be describing a comet, this theory is no longer considered tenable.

“This event cannot be a report of a comet, because Burchard used the term for a star (‘stella’) and not for a comet, and because Burchard had a very positive augury, which is impossible for comets that are widely known. worst omen,” wrote Bradley Schaefer, professor emeritus in the Department of Astronomy at Louisiana State University, in an article published in 2023 in Journal of the History of Astronomy. “The reported event is exactly as expected for a previous T CrB eruption and all other possibilities are strongly rejected, making the case for a T CrB 1217 eruption strong.”

An even better documented sighting of a blazing interstellar object took place in 1787, when British astronomer and Church of England minister Francis Wollaston reported the sudden appearance of a star exactly where T CrB is now located. The new star was observed four times by telescopes in late December of that year before the object completely disappeared in the inky black sky.

The last two occurrences of the object occurred in 1866 and 1946, suggesting that the event that causes the bright flare of T CrB recurs every 80 years or so. Astronomers are now able to track changes in T CrB despite its great distance, so they know the object will soon shine brightly again, just a little shorter than its normal 80-year mark.

The starburst from T Coronae Borealis is estimated to reach magnitude +2 during the upcoming event, placing it in the moderately bright category. If it sticks to its earlier pattern, it will remain visible for several consecutive nights, peaking in intensity in the middle of its appearance and then gradually disappearing.

T Coronae Borealis (T CrB) is located near the constellation Hercules and will become the most visible star in the sky for about a week. (Screenshot by BBC/YouTube)

A once – or maybe twice – in a lifetime event

In astronomical terms, what happens to T CrB is known as a nova event.

The star is actually a binary or binary star system consisting of a dense white dwarf and a larger red giant orbiting each other in unstable orbits. Every eight decades or so, when the stars are close, the white dwarf’s gravitational pull generates a nova event that mimics the stunning power of a star exploding in a supernova at the end of its life.

“The stars are close enough that when the red giant becomes unstable due to increasing temperature and pressure and begins to shed its outer layers, the white dwarf collects this matter on its surface,” NASA explained in a statement about the phenomenon.

“The soft, dense atmosphere of a white dwarf will eventually heat up enough to release thermonuclear radiation [fusion] reaction – which produces the nova we see from Earth.” NASA

The atmosphere formed on the surface of a white dwarf is composed of hydrogen, which is so explosive that when it reaches a critical temperature, it sets off a chain reaction of simultaneous destruction and creation, turning hydrogen into helium and releasing almost imaginable amounts of excess energy into the process. This is the same chemical reaction that powers the Sun and all other active stars, although the heat and light produced by the periodic nuclear fusion of the T CrB binary is much more intense.

Before T CrB comes into view, it always follows the same developmental sequence. In the pre-eruption cycle, the brightness first jumps before experiencing a sudden decrease in intensity. When this happens, his form is immediate.

“The T CrB Pre-eruption Dip already began in March/April of this year,” explained the American Association of Variable Star Observers (AAVSO) in a 2023 press release. “If the 2023 dip is similar in timing to 1945, then the primary the eruption should have occurred roughly 1.1 ± 0.3 years later, or in 2024.4 ± 0.3.”

If the timing of these starburst events holds in the future, the next T CrB occurrence will occur just after the turn of the next century. A small percentage of people alive today should also make an appearance due to this appearance, giving them a unique opportunity to experience a rare and unique astronomical phenomenon twice in their lifetime.

So get ready to experience this rare event soon!

Top image: Conceptual image of the T Coronae Borealis eruption predicted for late 2024. Source: NASA Goddard Space Flight Center

By Nathan Falde