Supernovae can be much more violent than we thought.

For the first time, astronomers have witnessed the explosion of a massive star into a fiery supernova, and the spectacle was even more spectacular than experts had predicted.

According to research published in the Astrophysical Journal, scientists began observing the doomed star, a red supergiant called SN 2020tlf and located approximately 120 million light years from Earth, more than 100 days before its latest catastrophic collapse. The researchers observed that the star burst with dazzling bursts of light as large balls of gas exploded from the star’s surface during that time.

The researchers noted that previous observations of red supergiants preparing to explode showed no signs of strong emissions, so these pre-supernova fireworks came as a big surprise.

In a statement, the study’s lead author, Wynn Jacobson-Galán, a researcher at the University of California, Berkeley, said: “This is a milestone in our understanding of what huge stars do moments before they die.” “We saw a red supergiant star explode for the first time!”

When the big stars explode

In terms of volume, red supergiants are the largest stars in the cosmos, measuring hundreds or even thousands of times the radius of the sun. (Despite their size, red supergiants are neither the brightest nor the most massive stars in the sky.)

These huge stars, like our sun, create energy through nuclear fusion in their cores. Red supergiants, on the other hand, can generate elements considerably heavier than the hydrogen and helium that our sun burns because they are so massive. The cores of supergiants become hotter and more pressured as they burn larger components. These stars eventually run out of energy as they begin to fuse iron and nickel, their cores collapse, and their gaseous outer atmospheres are ejected into space in a violent type II supernova explosion.

Scientists have detected red supergiants before they become supernovae and analyzed the consequences of these cosmic explosions, but they have never before observed the entire process in real time.

In the summer of 2020, the authors of the new study began studying SN 2020tlf, when the star was flashing with dazzling bursts of radiation that scientists later interpreted as gas gushing from the star’s surface. Researchers tracked the irritable star for 130 days using two telescopes in Hawaii: the University of Hawaii Institute for Astronomy’s Pan-STARRS1 telescope and the WM Keck Observatory on Mauna Kea. The star finally exploded at the end of that time frame.

Researchers noticed a dense cloud of gas surrounding the star at the time of its explosion, which they believe was the same gas that the star had ejected in the previous months. This shows that the intense explosions began long before the star’s core disintegrated in the fall of 2020.

“Until now, we have never seen such dramatic activity in a dying red supergiant star, where we witness it emit such bright emission, then collapse and burn,” study co-author and UC Berkeley astrophysicist said in a statement. Raffaella Margutti.

These findings show that red supergiants undergo major internal structural changes, resulting in chaotic gas explosions in their final months before collapsing, according to scientists.