Astronomers spotted a red supergiant just before it exploded in a massive supernova

Key Takeaways:

1. Astronomers observed a red supergiant 130 days before it exploded in a supernova, using telescopes in Hawaii.
2. This discovery marks the first time a red supergiant was seen undergoing significant changes before a supernova.
3. The red supergiant showed bright radiation bursts, indicating tumultuous gas ejections before its collapse.
4. Researchers detected dense circumstellar debris around the star, revealing new details about stellar evolution.
5. This finding will help astronomers identify other stars on the verge of exploding by looking for similar radiation signs.

It was discovered just 130 days before exploding using two telescopes in Hawaii, allowing a team of experts to investigate it before it exploded in a massive supernova.

“This is a breakthrough in our understanding of what massive stars do moments before they die,” said Dr. Wynn Jacobson-Galán, the study’s lead author.

“The direct discovery of pre-supernova activity in a red supergiant star has never been observed in an ordinary Type II supernova.

“For the first time, we saw a red supergiant star explode!” Dr. Jacobson-Galán concluded.

The discovery, made before the supergiant detonated that autumn, is described in a research published in The Astrophysical Journal.

Using the Keck Observatory’s Low Resolution Imaging Spectrometer (LRIS), the researchers discovered dense circumstellar debris encircling the star when it burst.

The researchers believe this is the same gas that first alerted them to the red supergiant with a burst of brilliant radiation in the summer.

They claim the discovery exposes new facts about how red supergiants evolve just before exploding, as previously detected supergiants showed no signs of strong eruptions (such as the one that alerted researchers to the star’s existence) before collapsing.

Because the team was able to monitor this star for so long, they discovered that red supergiants “undergo significant changes in their internal structure, which then results in the tumultuous ejection of gas moments before they collapse”.

The discovery means that other observatories undertaking transient surveys will be able to look for similar sorts of bright radiation that could indicate other impending supernovae.

“I am most excited by all of the new ‘unknowns’ that have been unlocked by this discovery,” Dr. Jacobson-Galán stated.

“Detecting more events like [this] will dramatically impact how we define the final months of stellar evolution, uniting observers and theorists in the quest to solve the mystery on how massive stars spend the final moments of their lives.”

What are red supergiants?

Red supergiants are the largest stars in the cosmos by volume, yet they are not the most dense or brightest stars in the sky.

They are formed when a moderately massive star burns through the hydrogen at its core and begins to fuse helium, which produces heavier elements like carbon and iron.

However, hydrogen fusion continues in the outer shells, forcing the star to expand – and as its surface area increases, it becomes cooler.

Heavier and heavier elements continue to fuse within the core of a red supergiant until, astronomers believe, it forms an iron core that cannot sustain nuclear fusion, causing the star to explode.