The end of life of a red supergiant star was first observed by a team of astronomers. Using the Pan-STARRS telescopes and the Keck Observatory, they conducted more than 100 days of observation of the star, managing to follow in real time its collapse in on itself until it exploded in a spectacular supernova.
Wynn Jacobson-Galán, lead author of the study, celebrated the observation. “This is unprecedented in our understanding of what massive stars do before they die,” he explained. “Direct detection of pre-supernova activity in a red supergiant star has never been observed before in a common type II supernova.”
There are several types of supernovae, and one of them represents the “last breath” of a massive star—Type II supernovae, for example, come from the death of a star more than eight times the mass of the Sun. the first detection of a star through the large amount of light emitted by it; a few months later, a supernova lit up the sky. The authors wasted no time and analyzed the first spectrum of the SN 2020tlf explosion with the spectrometer at the Keck observatory.
Want to catch up on the best tech news of the day? Access and subscribe to our new youtube channel, Kenyannews News. Every day a summary of the main news from the tech world for you!
Upon analyzing the data, they found evidence of dense circumstellar matter surrounding the star at the time of the star. This is likely to be the same gas that Pan-STARRS observed the supergiant star expel a few months earlier. They continued to monitor SN 2020 tlf after the explosion, and determined that the supernova was caused by a red supergiant star in galaxy NGC 5731 with 10 million solar masses, located about 120 million light years from Earth.
So far, all the red supergiants observed before they exploded showed no evidence of violent eruptions or light emissions, contrary to what SN 2020tlf did. In addition to challenging the conception of how supergiants evolve before they explode, detecting radiation coming from a red supergiant just before it explodes suggests possible processes taking place in these stars.
It is possible that some of them present significant changes in their internal structures, which result in the intense ejection of gas a few moments before the final collapse. “It’s like watching a time bomb,” noted Raffaella Margutti, co-author of the study. “Until now, we’ve never confirmed such violent activity in a dying supergiant star, where we see it produce such a bright emission, collapse and combust.”
Now, the team hopes to observe more red supergiant stars in the pre-eruption stage to better understand what happens in the final days before the supernova happens. “Detecting more events like SN 2020tlf will dramatically impact how we define the final moments of stellar evolution, bringing together observers and theorists in the quest to solve the mystery of how massive stars spend the final moments of their lives,” concluded Jacobson-Galán.
The article with the results of the study was published in The Astrophysical Journal.
