Some very bright supernovae could come from the creation of particle and antiparticle pairs. A group of astrophysicists think they have observed the first indisputable example of this type of star explosion with antimatter: SN 2016iet.
Nearly 50 years ago, several theoretical astrophysicists predicted that some stars were unstable because of a phenomenon well described by the equations of quantum electrodynamics. Indeed, with a sufficiently energetic pair of gamma photons, a calculation carried out with the help of the famous Feynman diagrams, well known to the specialists of the high energy physics, indicates that pairs of particle-antiparticle can be created.
In the case of a very massive star exceeding 100 solar masses, many of the photons produced by the thermonuclear reactions in the heart of these stars are in the gamma domain. However, they can each give birth to a pair of electron-positron if they have enough energy. It is basically a fairly simple consequence of Einstein ‘s formula, the energy of the photons being converted into the mass of the two particles.
When the creation of matter and antimatter according to this process becomes important, the pressure of the flux of gamma photons on the layers of the star becomes insufficient to oppose its contraction under the effect of its own gravity , because a part radiation is converted into a component that behaves like a mixture of gases at lower pressure. However, this same contraction will increase the rate of nuclear reactions by heating the heart of the star. The production of gamma photons creators of antimatter will be further increased and the process becomes unstable when the star contains at least 130-140 solar masses (below, there is oscillation and the star becomes pulsating). He’s racing.
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