For the first time in history, we have obtained direct observational evidence of the stellar processes that produce neutron stars and black holes. Astronomers observed that a supernova occurred in a nearby galaxy, producing objects with the properties of neutron stars and black holes. This discovery confirms that the collapse of the cores of massive stars creates the densest objects in the universe. Massive black holes and neutron stars are thought to form through similar processes. When the fuel to support nuclear fusion runs out, the star loses its external pressure and its core collapses, forming an ultra-dense object. The properties of such objects are determined by the mass of the star. For example, a star smaller than eight solar masses turns into a white dwarf.
Our understanding of these processes is primarily based on observations of the effects of neutron stars in the Milky Way, for example. However, it has been impossible to observe supernovae in our galaxy for centuries. But the supernova SN 2022jli, which exploded in the spiral galaxy NGC 157 just 75 million light-years away, presented a unique opportunity. Its peculiarity is a periodic change in brightness every 12.4 days over 200 days, which was first detected in the light curve of a supernova. A team of astrophysicists led by Ping Chen of the Weizmann Institute of Science suspected that SN 2022jli had a binary companion star that survived the explosion. They discovered gamma-ray bursts and hydrogen movement at the site of a supernova explosion. Their analysis revealed that the brightness changes are likely caused by interactions between the remnants of SN 2022jli and its companion star. This discovery means that SN 2022jli is the first supernova for which astronomers were able to observe the formation of a compact object in real time.
A team of astrophysicists led by Ping Chen of the Weizmann Institute of Science suspected that SN 2022jli had a binary companion star that survived the explosion. They discovered gamma-ray bursts and hydrogen movement at the site of a supernova explosion. Their analysis revealed that the brightness changes are likely caused by interactions between the remnants of SN 2022jli and its companion star. This discovery means that SN 2022jli is the first supernova for which astronomers were able to observe the formation of a compact object in real time. It is the culmination of decades of observation, analysis, and theory. Our understanding of black holes and neutron stars continues to deepen. “Our research is like putting together a puzzle by collecting all kinds of evidence,” Chen says. “All these elements together lead us to the truth.”
source: https://www.nature.com/articles/s41586-023-06787-x