|In the last year of his life, the impression of an artist of the red supergiant star, the stormy clouds of air come out. This suggests that some of these stars underwent significant internal changes before leaving the supernova. Credit: WM Cake Observatory / Adam Makarenko|
The star’s death is one of the most dramatic and violent events in space, and astronomers have found an unprecedented place at the explosive end of a giant star.
Ground-based telescopes provide the first real-time view of the death of a Red Supergiant star.
While these are not the brightest or largest stars, they are the largest by volume. One popular red supergiant that attracts interest due to its irregular eclipse is the BattleJues.
The star is located in the NGC 5731 galaxy, about 120 million light-years from Earth it was ten times larger than the Sun. Before they go out in splendor, some stars experience violent explosions or release bright layers of hot gas.
Until astronomers witnessed this phenomenon, they believed that the red supergiants were relatively quiet. Before they explode into supernovae or crash into dense neutron stars.
Instead, scientists saw the star dramatically self-destruct before it crashed into a Type II supernova. The star’s death is the rapid collapse and violent explosion of a giant star when it burns hydrogen, helium, and other elements at its core.
All that is left is the star’s iron, but the iron cannot fuse so the star’s energy will run out. When that happens, the iron breaks down and causes a supernova. A study detailing these findings, published Thursday in The Astrophysical Journal.
“This is a breakthrough in our understanding of what big stars do before the moment of death,” said Vin Jacobson-Gal, author of the lead study, a National Science Foundation Graduate Research Fellow at the University of California, Berkeley, in a statement.
“The direct diagnosis of pre-supernova activity in a red supergiant star has never been seen before in a normal type II supernova. For the first time, we have seen a red supergiant star explode.”
Astronomers were first warned about its unusual activity 130 days before the star went supernova. In the summer of 2020, the University of Hawaii Institute for Astronomy discovered the Pan-Starrs Telescope on the Mayan Halakala.
Then, in the fall of that year, researchers spotted a supernova at the same location.
They observed it using the WM Cake Observatory’s Low Resolution Imaging Spectrometer at Maunakea, Hawaii and named it Supernova 2020tlf. Their observations show that there was material around the star when it exploded – the bright gas that the star violently removes from itself over the summer.
“It’s like seeing a time bomb,” said Rafaela Margutti, a senior study author and associate professor of astronomy and astrophysics at UC Berkeley. “We have never confirmed such violent activity in a dying red supergiant star where we saw it produce such a bright emission, then collapse and burn, so far.”
Some of these larger stars probably experience the resulting internal changes that cause turbulent release of gas before their death, the findings show.
The work was carried out while Jacobson-Gallen and Margutti were still at Northwestern University. They had remote access to the Cake Observatory’s telescopes in Hawaii, which was intended to provide “direct evidence of the transition of a large star into a supernova explosion,” Margutti said.
“I’m really excited about all the new ‘strangers’ unlocked by this discovery,” Jacobson-Gala said. “Discovering more events like SN 2020tlf will dramatically influence how we define the final months of stellar evolution, uniting observers and theorists to unravel the mystery of how giant stars spend the last moments of their lives.”