Image source, NASA
The explosion of the white dwarf star T Corona Borealis, or the Northern Crown star. It happens every 80 years.
The world's attention was originally focused on the impending total solar eclipse. But actually there is another phenomenon this year that may be more interesting. Due to the constellation of the Northern Crown, it consists of a white dwarf and an ancient red giant. The countdown to the amazing Nova explosion is underway.
The constellation of the Northern Crown, or Corona Borealis, is 3,000 light-years away from Earth, and the star that will explode is the white dwarf star called “T Corona Borealis” or “T CrB” for short, which is what NASA indicated. This nova explosion will be a phenomenon that you may only see once in your entire life.
The phenomenon of a nova explosion is expected to occur before September of this year and is likely to be visible to the naked eye. Without having to use an expensive telescope in any way
T CrB explosions only occur every 80 years, and the last time this happened was in 1946.
“I'm so excited. It's like waiting to see Halley's Comet. This happens every 75-80 years, just a nova explosion. Comets don't often get a lot of attention,” says William Cook, director of NASA's Meteor Environment Program. “The media tends to focus more on comets.”
Scientists predict how a nova will form.
Naturally, NASA experts don't know when a nova explosion will occur, but there are 10 nova events that we know of. “Repeat Nova”
“Recurrent novae are novae that occur over a period of time. There will be more explosions,” Cook explained. “North Corona is a good example.”
So how does NASA know when T CrB will explode? They use mathematical calculations and experimental evidence. For example, the Corona Borealis explosion occurred in 1946, or 78 years ago, meaning the clock is counting down.
Another sign that T CrB is about to explode is that “we know it's pre-nova, and the star will fade away in about a year, with Corona Borealis starting to fade in March 2023, so we think it's close to exploding. Between now and the end of September,” Cook said.
Image source, NASA
The repeated explosion rate of T CrB nova makes this star's explosion unique from other novae discovered in recent years.
Meredith MacGregor is an assistant professor in the School of Physics and Astronomy. Johns Hopkins University, which specializes in stellar activities, expressed your opinion on this topic: “We have discovered a lot of novae. But most of them are not recurring novae. Or it will take a long time for them to explode again. We don't even know when that will happen.”
Richard Townsend, professor of astronomy, University of Wisconsin-Madison added that the timing of recurring supernova explosions is uncertain, as it could be a year or even millions of years away.
What causes a nova explosion?
In addition to predicting the time of a nova phenomenon, NASA experts also know why novae occur? For example, the white dwarf T CrB is a binary star system, which means it is one of two stars orbiting each other. Another star in the same system is a red giant star
White dwarfs contain materials similar to that found in the Sun. But its radius around the star is more than 100 times smaller than the radius of the Sun, making it about the same size as Earth. But with the material packed into young stars this makes the white dwarf's gravitational force extremely large.
When red giant stars orbiting together release matter, the gravitational force of T CrB will attract that matter or accumulate and store it on the surface of the star itself. When it has accumulated over many years the amount of absorbed substance has reached its maximum.
“What happens in this binary star system is the red giants dump material onto the surface of the white dwarf,” Cook said. “It also causes a thermonuclear reaction. Just like a landmine exploding. Make the white dwarf explode and release this material.”
Townsend offered a similar explanation, saying that when large amounts of material accumulate on T CrB and temperatures rise to millions of degrees Celsius, a nuclear fusion reaction will begin. Causing observable nova explosions
“This is also a reaction that occurs in the core of the Sun. Because the red giant star released an enormous amount of energy onto the surface of the white dwarf,” Townsend said, “this causes the white dwarfs to briefly appear brighter than the red giants. That’s the light from the two stars when viewed.” of the world will increase primarily 1,000-100,000 the same amount only.”
This huge explosion helps NASA experts understand the mass transformation that occurs between two stars in binary systems. Thermonuclear explosions occur when a white dwarf star is supernova. These processes happen over and over again in this binary star system.
“Normally it would take thousands of years to be able to see a nova like this, but T CrB happened before that. It makes it a rare nova,” McGregor said.
What will you see when a nova occurs?
T CrB has a visibility of +10 in brightness, according to NASA. But when a nova explosion occurs the visual acuity increases dramatically, reaching level +2, which is much brighter than level +10.
Comparing to make it easy to understand visible magnitude +2 is equivalent to the brightness of the North Star or Polaris, meaning that when a nova occurs the naked human eye can see it.
For those who want to see a T CrB nova explosion, NASA recommends looking at the Northern Crown constellation. It is located near the constellation Shoes and Hercules. “This is where the nova explosion occurred. It will appear like a bright new star rising in the sky.”
If you see a light like a new star in the sky, we must understand that this is not the birth of a new star. Due to nova explosions and nuclear reactions it only allows us to see T CrB more clearly.
“This phenomenon is caused by an existing star. We have just seen something like the birth of a new star. Only because it is natural,” MacGregor explains: “We cannot see this star.” White dwarfs are too small to be seen with the naked eye. But because of the fusion reaction that takes place, it allows us to see it for just a moment.
Cook points out that when T CrB shines at its peak, it will be brighter than Mars. It will continue to shine brightly in the sky until it becomes visible to the naked eye for another 2-3 days, although the nova explosion lasted for more than a week.
When it's all over, that means the white dwarf removes material from the red giant and T CrB vanishes, becoming invisible to the naked eye for decades.