Astronomers witness red supergiant star’s death for the first time

Astronomers have captured the death of a red giant star for the first time.

The discovery was published in real time Jan. 6 in The Astrophysical Journal led by researchers at Northwestern University and the University of California, Berkeley.

According to a Northwestern press release, the team observed the giant red giant during the last 130 days before it collapsed into a Type II supernova.

Previous observations showed that the red giant planets were relatively inactive before their death, without any evidence of violent volcanic eruptions or luminous emissions.

However, these researchers detected bright radiation from a red giant in the last year before it exploded.

“This is a breakthrough in our understanding of what massive stars do moments before they die,” Wayne Jacobson Gallan, lead author of the study, said in a statement. “Direct detection of pre-supernova activity in a red giant star has not been observed before in an ordinary type II supernova. For the first time, we watched a red giant star explode.”

The work — which was conducted in Northwestern before Jacobson-Galán moved to UC Berkeley — suggests that at least some stars must undergo significant changes in their internal structure, expelling gas before collapsing.

The star was first discovered in summer 2020 by the University of Hawaii’s Pan-STARRS Institute for Astronomy and the group caught its flash a few months later.

The 2020tlf supernova spectrum was taken using the WM Keck Observatory’s Low Resolution Imaging Spectrometer.

The data revealed evidence of dense material around the star at the time of the explosion.

Additional post-blast observations and additional data from the Keck Observatory’s deep imaging and multi-body spectrograph and the near-infrared spectrograph Echellette Spectrograph helped researchers determine that the progenitor red giant star SN 2020tlf was 10 times larger than the Sun.

“I am very excited about all the new ‘unknowns’ that have been revealed through this discovery,” Jacobson Gallan said. “The discovery of more events like SN 2020tlf will greatly impact how we define the final months of stellar evolution, uniting observers and theorists in the quest to solve the mystery of how massive stars spend their last moments.”

The study was supported by NASA, the National Science Foundation, the Heising-Simons Foundation, the Canadian Institute for Advanced Research, the Alfred P. Sloan Foundation, and Villum Fonden.


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