The RS-Ophiuchi white dwarf turns out to be one of the most efficient particle accelerators in the universe. A team led by Alison Mitchell of the University of Erlangen-Nuremberg also determined that a new remnant supernova is accelerating protons and heavier atomic nuclei to their highest theoretically possible energies. The high-energy radiations emitted by novas, combined with computer models, show that the particles accelerated by the explosion have energies hundreds of times higher than in previous novas, The team reports in “Science”.. The finding highlights why some novae emit gamma rays and suggests that such frequent supernovae are an important source of high-energy cosmic rays.
RS-Ophiuchi is part of a binary star system whose components orbit each other at a distance between the Earth and the Sun. The compact white dwarf constantly pulls material from its partner and accumulates on its surface. If this mass exceeds a critical limit, nuclear fusion ignites and causes a thermonuclear explosion on the surface of the white dwarf. A total of nine such explosions have occurred since 1898. The last supernova was observed in August 2021 by the Namibian High Energy Stereoscopic System (HESS) gamma-ray telescope and the Fermi satellite.
In the case of supernovae, high-energy gamma rays are also produced by a mechanism that has only been partially elucidated so far. According to the HESS Nova program, managed by Mitchell, Monitor Nova’s workgroup for a month Revealing changes in light curves. The intensity of radiation decreases with time, while at the same time the spectrum expands. Experts interpret this as an indication of the mechanism of origin of the radiation recorded by the two telescopes: accordingly, the shock wave from the explosion accelerates the particles to huge energies. The force of the explosion seems to increase in the first two days, Because the intensity of higher energy gamma rays continues to increase during this periodbefore it starts to back off.
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