The new phenomenon of micronova: small but very powerful stellar explosions – Technology

The new phenomenon of micronova: small but very powerful stellar explosions – Technology

Terrestrial or spatial, telescopes have proved to be real aids in the study and analysis of various astronomical phenomena and, consequently, in the discoveries that help to better understand the universe and its origins. This time, a new type of stellar explosion, a micronova, was observed with the European Southern Observatory (ESO) Very Large Telescope (VLT) as a “service assistant”.

The micronova are described as extremely powerful events, but they are also small events on an astronomical scale; they are far less energetic than stellar explosions known as novae, which astronomers have known for centuries.

Both types of explosions occur in white dwarfs, “dead” stars with a mass comparable to our Sun, but as small as Earth in size, which means they are very dense objects.

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

The phenomenon challenges our understanding of how thermonuclear explosions occur in stars. We thought we already knew, but this discovery offers us a whole new way for this to happen.”, Adds the researcher.

A white dwarf in a binary system can “steal” material, essentially hydrogen, from its companion star if both are close enough to each other, explains ESO’s Science Outreach Network note. When this gas falls on the very hot surface of the white dwarf star, the hydrogen atoms fuse into helium quite explosively.

A white dwarf in a binary system can “steal” material, essentially hydrogen, from its companion star if both are close enough to each other, explains ESO’s Science Outreach Network note. When this gas falls on the very hot surface of the white dwarf star, the hydrogen atoms fuse into helium quite explosively.

In novae, these thermonuclear bursts occur across the entire stellar surface, causing the entire surface of the white dwarf to glow for several weeks, explains study co-author Nathalie Degenaar, an astronomer at the University of Amsterdam in the Netherlands.

Micronovae are similar explosions, but smaller and faster in size, lasting a few hours. They occur in some white dwarfs with strong magnetic fields, where the material is routed towards the magnetic poles of the star.

Although the “micro” implies that these events are small, we must not be fooled: only one of these explosions can burn about 20,000,000 billion kg of matter, or the corresponding to about 3.5 billion Great Pyramids of Giza.

These new micronovae challenge astronomers’ understanding of stellar outbursts and may be more abundant than previously thought.

This shows how dynamic the Universe is. These events can, indeed, be quite common, but because they are extremely fast, they end up being difficult to catch at the moment of the act,”Explains Scaringi.

The team first discovered these mysterious microbursts while analyzing data from NASA’s Transiting Exoplanet Survey Satellite (TESS).

Three micronovae were observed with TESS: two in known white dwarfs and a third requiring further observations, taken with the X-shooter instrument on ESO’s Very Large Telescope (VLT) to confirm that it was also a white dwarf.

The discovery of the micronova joins the repertoire of the well-known stellar explosions. The team now wants to capture more of these elusive events, which require large-scale screening and quick follow-up measurements.