For the first time, astronomers capture the dramatic end of the life of a red giant star.. Video

Weather of Arabia - For the first time, astronomers were able to photograph the dramatic end of the life of a red supergiant star, and watch the massive star's rapid self-destruction and its final dying stage before its collapse and transformation into a Type II supernova.

What is the significance of the astronomers' findings of depicting the death of a star?

What happened is that a team led by researchers at Northwestern University and the University of California, Berkeley (UC Berkeley), monitored the red giant star for the last 130 days before its deadly explosion, and new, previously unobserved observations turned up.

This discovery challenges previous ideas about how red giant stars evolved immediately before the explosion. Previous observations have shown that red giant stars are relatively quiet before their death, with no evidence of violent explosions or luminous emissions.

However, new observations revealed bright radiation from a red giant in the last year before it exploded. This suggests that at least some of these stars must undergo significant changes in their internal structure, which then lead to turbulent expulsion of gas moments before collapsing.

These observations were made when the team quickly captured the powerful flash and obtained the first spectrum of the energetic explosion, called the supernova (SN 2020tlf) using the Keck Observatory's Low Resolution Imaging Spectrometer in Hawaii. The data showed direct evidence of dense circumstantial matter surrounding the star at the time of the explosion.

"It's like watching a ticking time bomb," said Raffaella Margotti, assistant professor at CIERA and senior author of the study. "We have never, until this moment, confirmed such violent activity in a dying red giant star that we see it produce such a luminous emission, then collapse and ignite."

The team continued to observe the supernova (SN 2020tlf) after the explosion. Based on data obtained from the Keck Deep Imaging, Multi-Object, and Near-Infrared Observatory, the researchers determined that the exploding red giant star, located in the galaxy NGC 5731 about 120 million light-years from Earth - It was ten times more massive than the sun.

"I am very excited about all that has been revealed by this discovery," said Jacobson Gallan, lead author of the study. "The discovery of more events like SN 2020tlf will greatly impact how we define the final months of stellar evolution, uniting observers and theorists in the quest to solve the mystery of how massive stars spend their last moments."

How does the red giant star die?

We are not the only ones who are born and die. Almost everything with us in the universe falls into the same circle. And if you can look at death as a process of transition, from one state to another, it is not much different for stars, stars live long in the main sequence star stage based on the nuclear fusion reactions of hydrogen in the star's core that cause pressure outward where it is This pressure is balanced by the force of gravity acting inward.

The death of the star begins with hydrogen running out in its center, turning into helium, but it cannot escape from the center, and the hydrogen in the outer layers cannot return to the center, due to the radioactive zone surrounding it, and therefore, a small proportion of hydrogen is the fuel that it uses The star all his life is in the stage of the basic style.

When the hydrogen runs out, the pressure resulting from its fusion disappears, and the gravitational force becomes the controlling one, and the core begins to contract under the influence of its own gravity, yet the total size of the star increases as the hydrogen continues to merge in the outer layers, releasing large amounts of energy, which causes an increase in temperature. Thus increasing the total size, and turning the star into a so-called red giant (Red SuperGiant).

As a result of the reduction in the size of the center, its density increases, and thus its temperature increases to the point that it begins to act as a liquid and not a gas, and as we know that liquids are incompressible, therefore the contraction stops, but the temperature has increased enough to allow helium to start its own fusion reactions, transforming to heavier elements until it reaches carbon and oxygen.

The reactions complete their way after carbon and oxygen, as a large center mass means a higher temperature, and therefore the reactions continue to produce heavier elements such as silicon, neon, magnesium and others, until iron begins to appear, which is the heaviest element that can be found inside a star, but the temperature is not enough for its integration, and thus the appearance of iron It directly means that this star is gone, and that it is time to celebrate its death with a supernova called a supernova.

The word “Nova” in Latin means “new”, and with it the supernova is called (Supernova), because it causes intense shine in the sky, so it appears to the beholder as if there is a “new” star that has just been born.