The Blazing Star event first recorded in a medieval manuscript will return

An astronomical anomaly that was first observed and recorded more than eight centuries ago is set to return to Earth’s night sky. By September, a double star known collectively as T Coronae Borealis will ignite and make its presence known across the planet, shining with a low intensity that matches that of the North Star, Polaris. The newly visible star may be observable for up to a week before dimming and disappearing into the firmament again.

Although it is located about 3,000 light years from Earth, this variable stellar body (it has been nicknamed “the Blazing Star”) will be visible from many places, emerging like a beacon in a previously empty patch of sky inside the hard to spot space. constellation of the Corona Borealis, not far from the more visible constellations of Boötes and Hercules. This phenomenon will be the result of a violent interaction between the two stars that make up this double star system, which will generate a burst of light so intense that it will radiate through the Milky Way without fading for the equivalent of several days terrestrial.

A “wonderful sign” will be seen

The first recorded exposure 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 borders of Corona Borealis.

“A wonderful sign was seen,” he notes in a medieval manuscript, in the form of an object that “shone with great light” for “several 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 omen, which was impossible for comets which are universally the worst omens,” wrote Bradley Schaefer, professor emeritus in the astronomy department at Louisiana State University, in a 2023 article published in the Journal for the History of Astronomy. “The reported event is exactly as predicted for an earlier T CrB eruption, and all other possibilities are strongly rejected, so the case for the 1217 T CrB eruption is strong.”

An even better-documented sighting of the blazing interstellar object occurred in 1787, when British astronomer and Church of England minister Francis Wollaston reported the sudden appearance of a star precisely where the We now know that T CrB is found. He observed the new star four times using telescopes in late December of that year, before the object completely disappeared into the inky black sky.

The object’s last two appearances took place in 1866 and 1946 respectively, indicating that the phenomenon that causes the T CrB to break up occurs again approximately every 80 years. Astronomers are now able to track T CrB’s changes despite its great distance, and that’s how they know the object will brighten brightly again soon, just a little short of its normal 80-year marker.

The T Coronae Borealis starburst is estimated to reach a magnitude of +2 during the next event, putting it in the moderately bright category. If it follows its past pattern, it will remain visible for several consecutive nights, reaching a peak of intensity in the middle of its appearance before 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 BBC/YouTube)

A once in a lifetime event or maybe twice in a lifetime

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

The star is actually a double or binary star system, consisting of a dense white dwarf and a larger red giant that orbit each other in unstable orbits. Every eight decades or so, when the stars are close together, the white dwarf’s gravitational force generates the nova event, which mimics the astonishing violence of a star exploding as a supernova at the end of its lifespan.

“The stars are close enough that as the red giant becomes unstable due to its increasing temperature and pressure and begins to eject its outer layers, the white dwarf collects this material on its surface,” he said. explained the American space agency NASA in a press release on the phenomenon.

“The white dwarf’s dense, shallow atmosphere eventually warms enough to cause an uncontrollable thermonuclear (fusion) reaction, which produces the nova we see from Earth.” NASA

The atmosphere produced on the surface of the white dwarf is composed of hydrogen, which is so explosive that when it reaches a critical temperature, a chain reaction of simultaneous destruction and creation is triggered, converting the hydrogen into helium and releasing almost imaginable amounts of excess energy into the atmosphere. 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 binary star T CrB is much more intense.

Before T CrB explodes, it always follows the same developmental sequence. During the cycle preceding the eruption, its brightness first increases, before experiencing a sudden drop in intensity. When this happens, its appearance is imminent.

“The pre-eruption trough of T CrB has already started in March/April of this year,” explained the American Association of Variable Star Observers (AAVSO) in a 2023 press release. “If the 2023 trough is similar in timing to that of 1945, then the primary eruption is expected to occur approximately 1.1 ± 0.3 years later, or in 2024.4 ± 0.3.”

If the timing of these star explosions holds into the future, the next appearance of T CrB will be just after the turn of the next century. A small percentage of people alive today are also expected to be present for this apparition, 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 explosion planned for late 2024. Source: NASA Goddard Space Flight Center

By Nathan Faldé