Just when you think we know a lot about the stars above, something comes along that lights them up even more. Literally, in this case, thanks to the observation of a whole new type of supernova. The discovery has interesting implications for a mysterious bright light that appeared in the sky in 1054.
Posted in Nature astronomy On Monday, a report from an international team of scientists confirms an unprecedented type of star explosion. Before the discovery, it was thought that there were only two types of supernova: a core collapse supernova (which occurs when a massive star runs out of fuel and its heart collapses into a black hole or neutron star) and a thermonuclear supernova (which occurs when a white dwarf star explodes).
However, since the 1980s there was speculation that another type might exist. Ken’ichi Nomoto of the University of Tokyo predicted a third type called an “electron capture supernova” in 1980. It is a supernovae resulting from a shortage of fuel, which then had gravity force electrons in the atomic nuclei of the nucleus – thus collapsing in itself.
Evidence suggesting the existence of an electron-capturing supernova implies that huge stars lose much of their mass before exploding. The mass in question must be of an unusual chemical composition. After the supernova, there should be minimal radioactive fallout, and the core should contain elements rich in neutrons.
Spectral analysis of a supernova, originally detected in March 2018, provides new evidence for the theory of an electron-capturing supernova. Nicknamed “Supernova 2018zd”, several key factors suggest its electron-capturing nature: it displayed a large amount of its mass loss before exploding, has an unusual chemical makeup, produced a weak explosion, shows little radioactivity and leaves a neutron. – rich kernel.
Understandably thrilled to see his theory gain weight, Nomoto commented on the development and contributed to the article.
“I am very happy that the electron-capturing supernova has finally been discovered, which my colleagues and I predicted 40 years ago and has a connection to the Crab Nebula. It is a wonderful case of a combination of observations and theory “, mentioned.
The Crab Nebula Link
One of the brightest mysteries in supernova history, the origins of the Crab Nebula have long remained unexplained. It is believed that in 1054 AD, a supernova occurred in the Milky Way. Historical accounts claim that it was so bright that it could be seen in the daylight for 23 days and at night for almost two years. Nowadays, its remains are known as the Crab Nebula.
Although it has been the subject of extensive studies, it was difficult to determine whether the nebula was likely the result of an electron-capturing supernova, in large part because the explosion took place some time ago. nearly a thousand years.
With this new supernova discovery, however, it is believed that we can more confidently state that the Crab Nebula is the result of an electron-capturing supernova.
Dr Andrew Howell, head of the Global Supernova project and a member of the scientific staff at Las Cumbres Observatory, said: âThis supernova is literally helping us decode millennial recordings of cultures from all over the world. And it helps us associate something we don’t quite understand, the Crab Nebula, with something else that we have incredible modern records of, this supernova. “
âIn the process, he teaches us fundamental physics: how certain neutron stars are made, how extreme stars live and die, and how the elements that we are made of are created and scattered throughout the universe. “
With more to learn about this new type of supernova, it’s hard not to keep an eye on the night sky for new and exciting eruptions of immense luminosity.