Astronomers are finding micronovae, a new kind of stellar explosion

through Very large telescope (VLT) At the European Southern Observatory (ESO), a group of astronomers has observed a new type of stellar explosion: a micronova. These explosions take place on the surface of certain stars and could burn about 3.5 billion large star pyramids in Giza in a matter of hours.

“We have discovered and identified for the first time something we call a micronova,” explains Simone Scaringi, an astronomer at the University of Durham in the UK who led a study on these explosions published in the journal Nature.

“The phenomenon is challenging our understanding of how thermonuclear explosions happen in the stars. We thought we already knew that, but this discovery offers us a whole new way to make this happen,” he adds.

Micronovae are very powerful events, but they are also small events on an astronomical scale; they are much less energetic than the stellar explosions known as nova, which astronomers have known for centuries. Both types of explosions occur in white dwarfs, “dead” stars that have a mass comparable to our sun but are as small in size as Earth, meaning they are very dense objects.

A white dwarf in a binary system can “steal” material, mainly hydrogen, from its partner star if the two are close enough to each other. When this gas falls on the very hot surface of a white dwarf star, the hydrogen atoms fuse into helium quite explosively. In Novai, these thermonuclear explosions occur over the entire surface of the star.

“Such blasts cause the entire surface of the white dwarf to burn and glow brightly for several weeks,” explains another author of the study, Nathalie Degenaar, an astronomer at the University of Amsterdam in the Netherlands.

Micronovae are similar explosions, but smaller in scale and faster, and last only a few hours. They occur in some white dwarfs with strong magnetic fields in which material is directed toward the star’s magnetic poles.

“We saw for the first time that hydrogen fusion can also take place locally. Some white dwarfs have hydrogen at the bottom of the magnetic poles, so the fusion only takes place on these magnetic poles, ”said Paul Groot, co-author of the study and an astronomer at Radbound University in the Netherlands.

“This will cause microfusion bombs to explode with about a millionth of the force of a nova explosion; this will be called Micronova,” Groot continues. , which is equivalent to about 3.5 billion large pyramids from Giza.

These new micronovae challenge astronomers ’understanding of stellar explosions, and there may be more than previously thought. “This shows how dynamic the universe is. These events can actually be quite common, but because they are very fast, they are hard to catch at the moment of the act,” Scaringi explains.

The group initially discovered these mysterious microbursts while analyzing data from the TESS satellite (Mobile Exoplanet Survey satellite) From NASA. “Analyzing the astronomical data collected by TESS, we found something unusual: a flash of bright visible light that lasts only a few hours. When we looked more closely at the phenomenon, we found several other similar signs,” Degenaar says.

The team detected three micronovae on TESS: two in known white dwarfs and a third that required additional observations were collected with an X-shooter instrument mounted Very large telescope (VLT) from ESO to confirm that it was also a white dwarf.

“With VLT, we found that all of these flashes of visible light were produced by white dwarfs,” Degenaar says. “This finding was crucial for us in interpreting the results and finding the microveside,” Scaringi adds.

The discovery of microworts is related to a range of known stellar explosions. The team now wants to capture more of these hard-to-detect events, which requires large-scale screening and rapid follow-up measurements. “The rapid response of telescopes such as the VLT or ESO’s new technology telescope and the instruments available to complement them allows us to take a closer look at what these mysterious micronaves really are,” Scaringi concludes.

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