[▲ Imaginary drawing of a red supergiant that emits gas violently in the last year of life (Credit: WM Keck Observatory / Adam Makarenko)]
University of California, BerkeleyWynn Jacobson-GalánThe leading research group isThe last few months before a red supergiant leads to a supernova explosionPresented the research results on the activities in. This achievement is expected to be a breakthrough for a better understanding of the activity of dying massive stars.
■ The appearance of brightening 130 days before the supernova explosion was captured.
starHappens internallyNuclear fusion reactionAt the same time as shining as an energy source, it also supports itself so that it will not be crushed by its own weight.In adolescent to middle-aged starshydrogenThe nuclear fusion reaction is the energy source, but when the hydrogen in the central part is exhausted, the nuclear fusion reaction will occur around it, and the outer layer of the star will expand.Red SuperstarorRed supergiantWill evolve into.
The end of a star depends on its massIs thought to beRelatively heavy stars, more than eight times the size of the Sun, cause supernova explosions, leaving neutron stars and black holes.on the other hand,A relatively light star, less than eight times the Sun, evolves into a white dwarf without a supernova explosion.Is believed to be. For example, the Sun and Sirius become white dwarfs, while Betelgeuse is said to cause a supernova explosion.
September 16, 2020, later「SN 2020tlf」Hawaii’s asteroid terrestrial collision final warning system for a supernova named「ATLAS」Is detected.As a result of additional observations, this supernova is a galaxy about 120 million light-years away in the direction of “Boötes”.「NGC 5731」Occurred in“Type II Supernova”I found that it was.What led to the supernovaThe mass is about 10 times that of the sunA red supergiant born as a massive star in the world, at the time of the explosion.The diameter expands to about 1100 times that of the sun
It is estimated that it was.*… Also known as “core collapse type” and “gravitational collapse type” supernovae. Reference article:
“Electron-captured supernova” that was predicted to exist is finally observed Domestic amateur astronomers also contributedAccording to the research group, the area where SN 2020tlf occurred is under a project called “Young Supernova Experiment” aimed at detecting sudden objects (objects whose electromagnetic wave intensity suddenly increases like supernovae) in Hawaii. Astronomical survey system“Pan-STARRS”Observations have been made since January 2020 using. By ATLASApproximately 130 days before the detection of SN 2020 tlf, PanSTARRS later causes a supernova explosionRed supergiant brightens significantly
A red supergiant that violently emits electromagnetic waves and gas and then reaches a type II supernova (animation image) (Credit: WM Keck Observatory / Adam Makarenko)
[▲ How a red supergiant reaches a type II supernova after violently emitting electromagnetic waves and gas (animation image) (Credit: WM Keck Observatory / Adam Makarenko)]The brightening detected by PanSTARRS seems to be contrary to conventional understanding of supernovae.According to the announcement, any red supergiant that could be observed before the supernova explosion so farRelatively quietSo, it is said that no violent release or brightening of matter was shown. The results of this observation show that at least some of the red supergiants have undergone major changes in their internal structure just before the explosion.Possibility of violent gas release just before the star collapses
It became an indication of.Jacobson-Galán points out that there has never been a direct observation of pre-explosion activity in a red supergiant that led to a normal type II supernova.A breakthrough in understanding the behavior of massive stars just before death
That’s it. “In addition, the additional observation data after the detection of SN 2020 tlf shows the red supergiant that caused the supernova.High-density Hase SeishūIt is said to indicate that it was surrounded by (gas, dust, etc. that exist around the star).The research group was detected by PanSTARRSGas released by pre-supernova activityWhen,Isn’t this Hase Seishū the same thing?
I think.
Jacobson-Galán also said, “I’m very excited about the’unknown’that this discovery has brought about,” said a supernova like the SN 2020tlf in revealing what happened in the last few months of stellar evolution. We hope that further observations will have a major impact.
Succeeded in capturing the flash of light immediately after the occurrence of “Type Ia supernova” Observation equipment at Kiso Observatory, University of Tokyo
Image Credit: W.M. Keck Observatory/Adam Makarenko Source: WMケック Observatory /
Northwestern University
Sentence / Takehiro Matsumura