Usually, supernovas aren't discovered until well after they've taken place. One lucky group of researchers based at Northwestern University, however, were able to watch a star die in real-time, the first time in recorded history scientists were able to do that. In a study published earlier this month in the Astrophysical Journal, astrophysicist Raffaella Margutti compared the situation to a ticking time bomb.
Margutti and her group were able to watch a star for around 130 days before it went supernova, and they were able to document everything as part of their study.
"It's like watching a ticking time bomb," Margutti said in a statement paired with the study. "We've never confirmed such violent activity in a dying red supergiant star where we see it produce such a luminous emission, then collapse and combust, until now."
In short, the study says new observations changed what scientists thought they knew about the death cycles of red supergiant stars. Instead of going quietly—as quiet as an exploding star can go, that is—the new study suggests at least some red supergiants go through "significant changes" in their internal structure, causing a substantial amount of radioactive gas before they collapse in on themselves.
"This is a breakthrough in our understanding of what massive stars do moments before they die," study lead author Wynn Jacobson-Galán added. "Direct detection of pre-supernova activity in a red supergiant star has never been observed before in an ordinary type II supernova. For the first time, we watched a red supergiant star explode."
The star was first discovered during the summer of 2020, and is some 120 million light-years away from Earth. Since the star is too far to be seen by the naked eye, researchers used the University of Hawaii's Pan-STARRS telescope to complete their research.
Cover photo by W.M. Keck Observatory / Adam Makarenko