It is obvious that the red supergiant is too intense on his deathbed. The omens seen before the supernova explosion are

The observation of supernova explosions is great!

In April 2020, several telescopes, led by NASA's Hubble Space Telescope, observed supernova explosions in real time for the first time in observation history, which has been told here.

In addition, in September of the same year, another research team successfully observed the supernova explosion of a red supergiant in real time. At that time, the explosion was the first to identify radiation and became a major discovery that subverted the common sense of supernova explosions.

Because, so far, the red supergiant has suddenly exploded without any warning. It is said that this is the first time that such a violent radiation has occurred before the supernova explosion, suggesting that mysterious changes have taken place inside the stars.

A supernova explosion refers to

Let's talk about supernova explosions first.

Almost all the stars that twinkle in the night sky shine through the fusion reaction of hydrogen. As hundreds of millions of years of nuclear fusion continue, the hydrogen in the fuel decreases and is replaced by the accumulation of helium formed by the fusion reaction.

Soon, once the hydrogen is exhausted, the fusion reaction will weaken, the weight will not be supported, and the central part of the star will begin to collapse. Then, the helium left in the center is compressed and the temperature rises. After exceeding a certain temperature, the fusion reaction between helium begins, forming carbon, oxygen and so on. At the same time, due to the huge amount of energy generated, the stars bulge and become superstars.

The gravity of stars more than eight times heavier than the sun will continue to compress the central part, so there will be fusion reactions between carbon and oxygen, forming neon lights, magnesium, silicon, etc., and eventually forming an iron core in the center of the star. But there is no fusion reaction between iron, so here the star's fusion reactor stops. Then, due to self-weight, the iron core begins to contract sharply, and almost all the iron nuclei become neutrons. In this reaction, a large number of neutrinos are ejected from the center of the star, and the star is thought to break into pieces. This is called a supernova explosion, which actually means the death of the stars.

A star that is blown up before your eyes.

The explosion of a red supergiant supernova observed in September 2020 is the first real-time observation in history. And it has been observed several months before the explosion, this is thorough!

The red supergiant anomaly was first discovered by the supernova survey run by Young Supernova Experiment at the University of California, Santa Cruz. In the summer of 2020, Pan-STARRS in Maui observed unusual amounts of radiation from red supergiants in the NGC5731 galaxy 120 million light-years away. The observation lasted 130 days after that. "it's like watching a time bomb," said Raffaella Margutti, an associate professor at the University of California, Berkeley, a senior researcher in the team.

On September 16, a supernova explosion finally occurred, and the first flash and its spectrum, as well as the whole process after the explosion, were successfully captured in detail using the low-resolution comprehensive spectroscopy of the Keck Observatory on the island of Hawaii. "I can see the red supergiant exploding in front of my eyes! "Wynn Jacobson- Gala á n, a postdoctoral researcher, said in a press release issued by the Keck Observatory. In addition, Mr. Margutti

I also said that.

A team of researchers led by Jacobson- Gal á n and Margutti summarized these observations into research papers and published them on Astrophysical Journal.

Common sense of shoes and new mysteries

The supernova explosion, named SN2020tlf, is different from any type II supernova explosion previously observed.

In general, red supergiants are less active before a supernova explosion and do not experience subsequent violent explosions or expected strong flashes. However, SN2020tlf emitted intense radiation months before the explosion. Moreover, it is surrounded by rich peristellar material from before to during the explosion.

These observations show that all red supergiants will not usher in the last minute, at least some of them will cause great changes in their internal structure before they are blown up. At the same time, due to the pre-explosion "precursor radiation (Precursor Emission)" and the existence of peristellar material, the mass of the red supergiant is lost due to some internal mechanism of the planet, which is also considered to be energy (light) radiation. As a harbinger of an unpredictable supernova explosion, it may be a useful clue in the future.

Mr. Jacobson-Gal á n said in a press release

And comments. It is expected that the dramatic supernova explosion that subverts the common sense so far will be observed this time.

By the way, it is speculated that SN2020tlf's original red supergiant was 10 to 12 times the mass of the sun and about the size of Bertelgius. In this way, will Bertelgius have the same magnificent deathbed? Deformation, dimming, and so on, Bethel Gius, who has a little irregular activity recently, is also of great concern.

Reference:Astrophysical Journal,Keck Observatory, astronomy dictionary