Two teams of astronomers, while observing the aftermath of a supernova explosion (SN 2022jli), have found direct evidence of a supernova leaving behind a black hole or neutron star for the first time with the help of ESO’s Very Large Telescope (VLT) and ESO’s New Technology Telescope (NTT).
The supernova SN 2022jli was discovered in the spiral arm of the nearby galaxy NGC 157, located 75 million light-years away.
A supernova is a violent explosion that occurs when a massive star runs out of its nuclear fuel at the end of its life, i.e., when a massive star dies. After the explosion, only the ultradense core of the star remains, which is known as a compact object (black hole or neutron star).
Generally, we see a smooth and gradually declining light curve after the explosion of a supernova, as the brightness of a supernova simply fades away with time.
However, in the case of the supernova SN 2022jli, astronomers have seen very peculiar behavior. The light curve of SN 2022jli was declining gradually, but it was not smooth. They saw a 12.4-day periodicity of brightening and fading within the declining light curve.
Thomas Moore, the lead author of one team, said in a statement, “In SN 2022jli’s data, we see a repeating sequence of brightening and fading.”
“This is the first time that repeated periodic oscillations, over many cycles, have been detected in a supernova light curve,” Moore noted in his paper.
According to the conclusion of both the Moore and Chen (lead author of another team) teams, supernova SN 2022jli occurred within a binary system, meaning the star that created the supernova and left behind a compact object (black hole or neutron star) had a companion star.
The companion star was able to survive the explosion, but its atmosphere became puffier. The compact object and its companion star continued to orbit one another, with the compact object regularly stealing matter from the companion star’s puffy atmosphere. This accretion of matter was seen in the researchers’ data as regular fluctuations of brightness.
“Our research is like solving a puzzle by gathering all possible evidence,” Chen said in a statement. “All these pieces lining up lead to the truth.”
Two scientific papers have been published on the findings. The team led by P. Chen published a paper in Nature, and the team led by T. Moore published a paper in The Astrophysical Journal Letters.
These results were presented at the 243rd meeting of the American Astronomical Society held in New Orleans, USA, from January 7–11, 2024.
Please follow us on Facebook and Twitter to get latest space news, upcoming skywatching events and astronomy-related content.
