A new type of stellar explosion has been discovered
A new astronomical phenomenon has been discovered by a team of observations led by astronomer Dr. Simone Scaringi of Durham University, UK. The team used the European Southern Observatory in the Southern Hemisphere (ESO)’s Very Large Telescope (VLT) telescope to observe a new type of stellar explosion called Micronovae. The above explosion was called ‘Micronova’ because it was a micronuclear fusion explosion with regarding 1 millionth the strength of a nova explosion.
As such, a micronova is much weaker than the commonly known nova or supernova, but it is still a very strong explosion. Micronovas occur on the surface of a particular star, and one explosion can burn regarding 3.5 billion pieces of the Great Pyramid of Giza (regarding 20,000,000 trillion kilograms) of stellar material in just a few hours.
Dr Simon Scaringi, who led the observation, argued that the discovery of the new astronomical phenomenon might suggest a new mechanism for how thermonuclear explosions occur in stars. The research team’s Dr. Paul Groot also said the findings suggest that the mechanisms responsible for stellar explosions may be much richer than is known. The above study was published in Nature in April, and the follow-up study was also published in the Monthly Notices of the Royal Astronomical Society.
Super large telescope ⓒ ESO/Y. Beletsky
Smaller and faster than conventional nova explosions – found in certain white dwarfs
If the white dwarf, the last form of the Sun, constitutes a binary system, and the white dwarf comes close enough to the companion, it can suck up hydrogen and other substances from the companion. When this gas falls on the very hot surface of a white dwarf, it can trigger the fusion of hydrogen atoms into helium. These thermonuclear explosions in novae occur over the entire stellar surface and can cause the entire surface of a white dwarf star to burn and glow brightly for weeks.
The micronova revealed in this observation is similar, but smaller and faster, lasting only a few hours. This is known to occur in some white dwarfs with strong magnetic fields, which propel matter towards the star’s magnetic poles. Since hydrogen fuel may exist at the bottom of some white dwarf’s magnetic poles, fusion can only occur at these poles. This is the first observation that confirms that hydrogen fusion can also occur in a localized manner.
Imagination of the micronova phenomenon ⓒ ESO
According to the research team’s Dr. Nathalie Degenaar, the research team first encountered these micro-explosives when analyzing data from NASA’s Transiting Exoplanet Survey Satellite (TESS) mission. Flashes of bright light lasting for several hours were confirmed, and the above study began at the same time that these similar signals were found three times.
Changes in optical brightness of EI UMa and ASASSN-19bh © Scaringi et al. 2022
Two of them were confirmed to be found in white dwarfs, and the third required additional observation with a super large telescope for more accurate confirmation.
Optical brightness change of TV col ⓒ Scaringi et al. 2022
the universe is very dynamic
Dr. Scaringi explained that the above phenomenon is an example of how dynamic the universe can be, and that in fact, these phenomena can be very common. However, he added that it is very difficult to observe this phenomenon because it is so fast.
Extra Large Telescope © JL Dauvergne & G. Hüdepohl (atacamaphoto.com)/ESO
With the help of a large telescope, the research team confirmed that all optical phenomena originate from white dwarfs, and this enabled the research team to present new phenomena and mechanisms in astronomy textbooks. According to Dr. Scaringi, follow-up studies with enormous data are absolutely necessary to better understand the mechanism, so these studies are planned.
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