In the vast depths of the Universe, a jewel shines in the constellation of Corona Borealis: T Coronae Borealis (T CrB). This explosive binary system is not only fascinating for its beauty and place in the night sky, but also for its explosive and recurring nature. Residents of Concepción, Chile, will have the once-in-a-lifetime opportunity to witness one of the most impressive events in the cosmos in the coming months: the great T CrB eruption. Occurring about every 80 years, this eruption turns T CrB into a dazzling beacon in the sky, increasing its brightness dramatically. If you are lucky enough to observe this next eruption, you will be witnessing a phenomenon that may never occur again in your lifetime.
Discovered by Irish astronomer John Birmingham on May 12, 1866, T CrB made its first appearance as a nova with a spectacular explosion. This phenomenon was repeated in February 1946, when observers in England and at the Yerkes Observatory in the United States reported another bright eruption. These recurring explosions have captured the attention of astronomers and sky enthusiasts alike, who eagerly await the next celestial spectacle.
T CrB is normally a faint star, with an apparent visual magnitude of about 10.2 magnitudes, barely visible to the naked eye. However, during an eruption, its brightness increases dramatically to reach a magnitude of 2.0 magnitudes, comparable to the bright Polaris, the North Star. This dramatic increase in brightness makes T CrB a dazzling beacon at night.
T CrB is a fascinating binary system composed of a red giant of spectral type M3III and a peculiar white dwarf. The eruptions occur when the red giant transfers material to the white dwarf, causing thermonuclear explosions on its surface. These explosions are cyclical events, occurring approximately every 80 years, and the next eruption could happen any time before September, keeping skywatchers on tenterhooks.
The process that leads to these impressive eruptions begins when the red giant star transfers material to the white dwarf. This accumulated material eventually triggers a thermonuclear explosion, releasing an immense amount of energy and dramatically increasing the star’s brightness. The red giant has a mass of 1.12 times that of the Sun and a radius 75 times greater, while the white dwarf, although smaller, has a mass of 1.37 times that of the Sun and is 100 times more luminous than the Sun due to the energy released by the accretion of material.
From Concepción, locating T CrB in the night sky will be relatively easy, especially during its eruption phase. To find this celestial gem, look north and raise your gaze about 25 degrees above the horizon. Look for the constellation Corona Borealis, which has the characteristic shape of a semicircular or “crown.” Identify the second star from right to left and right next to this star you will find T CrB. During its eruption, its brightness will be comparable to that of Polaris, making it easier to identify.
T CrB will be especially visible until August 16 before we lose it over the horizon. Thereafter, it will gradually move northwestward, approaching the horizon and eventually losing sight of it.. This is a unique opportunity to observe one of the most spectacular phenomena in the night sky. Prepare to marvel at the beauty of the Universe and the power of T CrB, the pearl of the Corona Borealis.
