Presented on ZOOM live from ESO Chile June 10th at 7pm (Irish Time)
ABOUT THE LECTURE:
Supernovae
Thomas will discuss his recent work on SN 2022jli (https://www.eso.org/public/news/eso2401/) and go on to discuss supernovae more generally.
“Astronomers have found a direct link between the explosive deaths of massive stars and the formation of the most compact and enigmatic objects in the Universe — black holes and neutron stars. With the help of the European Southern Observatory’s Very Large Telescope (ESO’s VLT) and ESO’s New Technology Telescope (NTT), two teams were able to observe the aftermath of a supernova explosion in a nearby galaxy, finding evidence for the mysterious compact object it left behind.
When massive stars reach the end of their lives, they collapse under their own gravity so rapidly that a violent explosion known as a supernova ensues. Astronomers believe that, after all the excitement of the explosion, what is left is the ultra-dense core, or compact remnant, of the star. Depending on how massive the star is, the compact remnant will be either a neutron star — an object so dense that a teaspoon of its material would weigh around a trillion kilograms here on Earth — or a black hole — an object from which nothing, not even light, can escape.
Astronomers have found many clues hinting at this chain of events in the past, such as finding a neutron star within the Crab Nebula, the gas cloud left behind when a star exploded nearly a thousand years ago. But they had never before seen this process happen in real time, meaning that direct evidence of a supernova leaving behind a compact remnant has remained elusive. “In our work, we establish such a direct link,” says Ping Chen, a researcher at the Weizmann Institute of Science, Israel, and lead author of a study published today in Nature and presented at the 243rd American Astronomical Society meeting in New Orleans, USA.
The researchers’ lucky break came in May 2022, when South African amateur astronomer Berto Monard discovered the supernova SN 2022jli in the spiral arm of the nearby galaxy NGC 157, located 75 million light-years away. Two separate teams turned their attention to the aftermath of this explosion and found it to have a unique behaviour.
After the explosion, the brightness of most supernovae simply fades away with time; astronomers see a smooth, gradual decline in the explosion’s ‘light curve’. But SN 2022jli’s behaviour is very peculiar: as the overall brightness declines, it doesn’t do so smoothly, but instead oscillates up and down every 12 days or so. “In SN 2022jli’s data we see a repeating sequence of brightening and fading,” says Thomas Moore, a doctoral student at Queen’s University Belfast, Northern Ireland, who led a study of the supernova published late last year in the Astrophysical Journal. “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. “
Credit ESO.
ABOUT THE SPEAKER:
Dr. Thomas Moore, Queen’s University Belfast.
Field of study Physics with Astrophysics – First-Class Honours.