A thermonuclear supernova is an explosion of a white dwarf star after gaining mass from another star in a binary galaxy, a binary star. This white dwarf is a dense core of ash that remains after a bright star – a star about 8 times the mass of the Sun – reaches the end of its life.
A supernova explosion in an iron core occurs when a massive star — more than 10 times the mass of the Sun — runs out of nuclear fuel and its iron core collapses, producing a black hole or neutron star.
Between these two main types of supernova – there are still many subdivisions – there are electron-capturing supernovae. These stars stop fusion reactions if their cores are made of oxygen, neon, and magnesium – they’re not heavy enough to make iron.
Gravity is constantly trying to suppress stars, and what prevents most stars from collapsing is either fusion in the core caused by opposing forces, or, in a core where fusion has stopped, the atoms in the core cannot be held close to each other. . .
In an electron-capturing supernova, some of the electrons in the oxygen, neon, and magnesium nuclei of their atomic nuclei are knocked out in a process called electron capture. This removal of electrons causes the star’s core to collapse under its own weight, capturing supernova electrons.
If the star was a little bigger, it is possible that the elements in its core had coalesced into heavier elements, prolonging its life. So it’s kind of reverse moderation: a star is not light enough to avoid collapsing its core and not heavy enough to prolong its life and then dies in a different way.
This is a theory that has been formulated since 1980 by Kenichi Nomoto of the University of Tokyo and other scientists. For years, theorists have been making predictions about what to look for when searching for electron-trapping supernovae and their precursors, giant super-enclosed sub-stars.
The stars must have had a lot of mass, much of it lost before the explosion, and the mass near the dying star must have had an unusual chemical composition. Then, the electron-capturing supernova must have a weak explosion, give little radioactive precipitation, and have a neutron-rich element in its core, because electrons are squeezed into atomic nuclei and many protons turn into neutrons.
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