Study confirms supernovae create neutron stars and black holes

10 Jan 2024

A star goes supernova in a binary system. Image: ESO/L Calçada

With the help of ESO telescopes, an international team of scientists led by Ping Chen have been able to closely observe the aftermath of a nearby supernova.

It has been long known that supernovae – the term given to the violent death of a massive star – end in the creation of two types of spectacularly dense objects: neutron stars and black holes.

While this understanding has historically been the result of clues that hint to this chain of events, scientists had never been able to witness a supernova to confirm the hypothesis.

Now, a group of international astronomers led by Ping Chen of the Weizmann Institute of Science in Israel has found the “missing link” by directly observing the aftermath of a supernova in the nearby galaxy NGC 157, located 75m light years away.

With the help of the European Southern Observatory’s Very Large Telescope and the New Technology Telescope, two separate teams of scientists were able to observe the aftermath SN 2022jli supernova and found it to have a unique behaviour.

Usually, the brightness of supernovae fades away with time as astronomers see a smooth and gradual decline in the explosion’s luminosity. In the case of this particular supernova, the brightness didn’t decline as expected – instead oscillating every 12 days.

“In SN 2022jli’s data we see a repeating sequence of brightening and fading,” said Thomas Moore, a doctoral student at Queen’s University Belfast 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 wrote in his paper.

Chen, who is lead author of a study published in Nature today (10 January), said that his team was able to establish this “direct link” for the first time.

Both Chen and Moore believe the unique behaviour of SN 2022jli could be explained by the presence of more than one star in the system, known as a binary system.

However, the teams says that what is remarkable about this explosion is the fact that the companion star seems to have survived the supernova and is in mutual orbit around the resulting compact object.

Despite not being able to observe light coming from the compact object itself, the team concluded that this “energetic stealing” is likely because of an unseen neutron star or black hole attracting matter from the companion star’s atmosphere.

“Our research is like solving a puzzle by gathering all possible evidence,” Chen said. “All these pieces lining up lead to the truth.”

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Vish Gain is a journalist with Silicon Republic