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‘Micronova’ explosions spotted on distant zombie stars

Stargains can occur in very different weights, from large supernovae to old novae. Now, scientists think they have identified an even smaller way in which the surface of the star could explode – dubbed “micronova.” It is a type of explosion that occurs in one region of the surface of some stars, which lasts for hours at the same time but is still very severe.

In particular, micronovae occur in a type of zombie star called a white dwarf. These supernatural objects are the nucleus of the dead stars, the remnants of celestial bodies like our sun that used all their fuel and put most of their material into space. The white dwarfs are very small but very dense, sometimes the same size as the ground but similar to the density of the sun. They are Hidden objects usually present some strange, and in the right conditions, micronovae may fall on top of them.

It is a type of phenomenon that scientists do not know exists until now (although the term micronova has been used. to refer to others shays.) Discovery, detail today that Nature, can change our understanding of the different ways stars can explode. Simone Scaringi, an astronomer at the University of Durham, is also the lead author Nature study, says Qarka. “How things change quickly if you don’t look at the right place at the right time.”

Scaringi and his team stumbled upon this mysterious event all of a sudden. They were working with the NASA satellite TESS, a space-based telescope developed in 2018 that is designed to locate planets outside our Solar System orbiting nearby stars. However, the group did not look for exoplanets; they used a telescope to study the brightness differences of hundreds of stars.

Scaringi is often interested in learning about white dwarves, especially those near the stars. Most of the Stars of the Universe come in pairs around each other. The two-pointed star Scaringi studied consists of white wool floating on a star like our Sun. When this configuration occurs, the densely packed surface will actually act as empty; Its large gravitational pull will begin to absorb hydrogen from the nearest star.

Eventually, the entire surface of the white wool will be covered with a layer of hydrogen. And, at some point, the pressure in that layer is so high that it causes a thermonuclear explosion. “The whole layer heats up with a bright light and burns all the density it has accumulated,” Scaringi said. The white dwarf still remains as soon as the incident is over, but the stolen hydrogen layer is on fire. This type of event is called nova, scientists have known about it for centuries.

An artistic view of the clear edge of the binary system, where micronova may occur.
Photo: ESO / M. Kornmesser, L. Calcada

But when Scaringi and his team looked at these unique white fur patterns, they saw something different. The team found that one white wool would shine for a short time – only 10 hours or more. “It was very bright and occasionally hit one thing,” Scaringi said. “We have no idea what we have been looking for for a year.” The shiny cracks are too small and too short to become a normal nova, which usually takes weeks at a time.

Then the team felt the short shining events of the same fall on two other white, as well as binary systems. That’s when they started assembling the parts. They realized that all three of these white fur had a very strong magnetic field. The team is amazed that hydrogen is pulling its white rays from its stars and flowing into the metal masses of the stars.

An equivalent of how this method works can be found here on Earth with aurora. Our planet also has a magnetic field, which is activated by the movement of the liquid core in the Earth. The promoted objects emanating from our Sun will often be trapped in our magnetic field, where the magnetic poles in the north and south of our planet will be deployed. That is what creates the aurora – also known as’ Northern or Southern Lights: Solar-powered objects collide with our atmosphere at these two locations.

The Scaringi team thinks the same thing is happening to these white animals, with other explosive effects. The white dwarfs’ magnetic fields direct objects moving from their companion to very small regions near the figures. When the material accumulates in these local environments, it eventually triggers a high-temperature explosion – except that they are much smaller than normal nova in between. Researchers estimate that these phenomena are about 1 million times smaller than normal nova, but they are still burning more objects (about the size of the larger asteroids in the Solar System).

Researchers have considered other possible explanations for light, including solar flares, but none of them are suitable for their observation. Of course, there is nothing 100% scientifically certain, especially when it comes to new discoveries. And, there is still something unknown about these phenomena, such as the exact mechanism that can trigger a micronova explosion. It is also unclear how often they occur, although researchers think they may occur more often than we expected. “A lot of systems might do it, and they might repeat it,” Scaringi said. “But just because they last up to 10 hours, maybe 12, if you don’t look at that thing, it will never show up.”