stellar

The sky is as mysterious as it is fascinating. In case it wasn’t enough to have this week the most unpredictable meteor shower of the yeartonight a new star could also appear out of nowhere in the sky. Okay, it doesn’t really appear out of nowhere. It’s always there. The thing is that it is usually invisible to our eyes; But, if an astronomer’s predictions come true, a brutal explosion could make it visible for a few days from today. This is the white dwarf T. Coronae Borealis. This is a binary system composed of a red giant and a white dwarf, in which one of the few recurring novae also forms. of the Milky Way. Until now, only 5 of these explosions have been documented that are repeated from time to time, drawing a new bright point in the sky. The last time T. Coronae Borealis “exploded” was in 1946. It is clear that the next explosion must be soon, although few scientists dare to give a date. Astronomer Jean Schneider, from the Paris Observatory, did dare some time ago to provide 4 possible explosion dates. The first three were not fulfilled. The last one is tonight. Better to look at the sky in case the flies. Most scientists believe that the next explosion of this recurring nova must be soon, but they believe that there is no way to calculate an exact date. However, Schneider has a different hypothesis. Although T. Coronae Borealis has always been considered a binary system, he believes that, in order for the explosions that have already been documented to occur, a third astronomical object is necessary. This would not only increase the intensity of the explosion, but also makes calculations easier. Thanks to that, he estimated four dates. The first three have passed without pain or glory. The last one is the night of this June 25. Therefore, he recommends setting your sights on the constellation Corona Borealis and looking for a new bright point. As bright as the North Star. Companion stars that engulf each other. Beyond Schneider’s predictions, what is known at the moment is that in T. Coronae Borealis, located 3,000 light years from Earth, there are two stars: a red giant and a white dwarf. Both rotate around each other, with an orbit of 227 days, in a process in which, from time to time, the red giant becomes unstable due to an increase in pressure and temperature and begins to expel its outermost layers into space, forming an accretion disk around it. Little by little, the gravitational attraction of the white dwarf pushes the material from that accretion disk towards it. In a way, the white dwarf “feeds” on its companion. It is a process in which the atmosphere heats up, until a very intense thermonuclear reaction occurs in the form of an explosion. A change of brightness. Normally, T. Coronae Borealis is magnitude 10. This equates to a brightness that is minimally on the edge of what can be seen with binoculars. The brightness increases inversely proportional to the magnitude: if it decreases, the star appears brighter. When the explosion occurs, the magnitude drops abruptly to a figure between 2 and 3, making it look very very bright. For a few days, a little less than a week, it shines brightly. similar to that of the polar star. Blasts from the past. This phenomenon was observed in 1866when the magnitude fell to 2, and in 1946, when it was around 3. In the second case it was possible to study much more thoroughly and something interesting was seen. That the magnitude did not suddenly fall from 10 to 3, but rather, as the white dwarf warmed its atmosphere, signs began to be detected. Starting in 1938, the magnitude had begun to decrease to 9 and the star’s brightness was more bluish. He was getting ready. The constellation is located between Hercules and Bootes It’s happening. After the 1946 explosion, the magnitude of T. Coronae Borealis was fixed at 10.2. However, in February 2015 it dropped to 10. It was a striking figure, which became even more interesting just a year later, when in 2016 it dropped again to 9.2. The shine also began to look more blueish. The same thing was happening as in 1938 and since then there have continued to be fluctuations around 9. Since then it was 8 years until the explosion, it was calculated that there should be another explosion in 2024, but it never occurred. We are already in 2026 and at the moment nothing; But, for Schneider, the moment of truth could be today. You can track the brightness. There are websites where you can track the brightness of the stars. This is, for example, the case of the website of the American Association of Variable Star Observers. In it, when entering T CrB in the search engine, we see that the magnitude is currently 9.9. Most experts believe that Schneider does not have sufficient evidence of the existence of a third object to validate his observations. The shine does not seem to have fallen again. Still, at some point the explosion should occur. What if you don’t go out to look and you miss it? Image | NASA | E. Slawik/NOIRLab/NSF/AURA/M. Zamani In Xataka | We have been studying the planets of TRAPPIST-1 for years with great hope. James Webb just knocked it down