A new type of stellar explosion could help us understand thermonuclear outbursts on dead stars.
Micronovae occur on the surface of white dwarf stars that are slurping down material from a close companion. A thermonuclear burst is caused by the accretion of material onto the white dwarf.
Astronomers say these explosions have burned through hundreds of quintillions of stellar material in hours.
This is in the vicinity of several billion Great Pyramids of Giza, according to the researchers. Around a thousandth of the Moon's mass is what you can compare it to.
Simone Scaringi of Durham University in the UK says that they have discovered and identified for the first time what they are calling a micronova.
The phenomenon challenges our understanding of how thermonuclear explosions occur. We thought we knew how to achieve them, but this discovery proposes a completely new way to do it.
White dwarfs can be used as thermonuclear explosion machines. A white dwarf is a star that has run out of fuel and ejected its outer material. There are other stars of this kind in different mass classes.
The collapsed core is very dense. White dwarf stars have a mass up to four times that of the Sun and are packed in a sphere the size of Earth. Many of them can be found in the same system.
A recurrent nova is caused by the white dwarf stripping material from the companion in some cases.
As the stars whirl around each other, material is taken off the companion by the smaller, denser white dwarf. The hydrogen accumulates on the white dwarf's surface.
The mass becomes so great that the pressure and temperature at the bottom of the layer are enough to cause a thermonuclear explosion. That is the nova.
A small version of the explosion was found by Scaringi and his team.
The white dwarf was first identified by the researchers using the TESS exoplanet-hunting telescope. TESS can be used to find small brightness variations in stars with exoplanets.
The team discovered micro novae when they found a brief flash of light from a white dwarf star. There were similar events in other white dwarfs. They found three bursts, the third of which led to the discovery of a previously unknown white dwarf star.
The flashes were too small to be a nova. The team wanted to find a scenario that would explain the observations. Micronovae was the most likely explanation.
A white dwarf with a powerful magnetic field can snatch material from its companion. The material accumulates at the white dwarf's poles, where it can cause an eruption similar to a white dwarf nova.
For the first time, we have seen that hydrogen fusion can happen in a local way.
The hydrogen fuel can be contained at the base of the magnetic poles of some white dwarfs. Micro-fusion bombs have about one millionth of the strength of a nova explosion, which is why they are called micro nova.
A decades-long mystery could be solved by the finding. Over the last 40 years or so, one of the white dwarfs in the system TV Columbae has been observed displaying similar flashes. There have been reports of similar bursts on other white dwarfs. This explanation could explain why.
Astronomers will need to collect more observations in order to understand the bursts better.
It goes to show how dynamic the Universe is.
The research has been published.
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