A team of astronomers, with the help of the European Southern Observatory’s Very Large Telescope (ESO’s VLT), have observed a new type of stellar explosion — a micronova.
These outbursts happen on the surface of certain stars, and can each burn through around 3.5 billion Great Pyramids of Giza of stellar material in only a few hours.
“We have discovered and identified for the first time what we are calling a micronova,” explains Simone Scaringi, an astronomer at Durham University who led the study.
“The phenomenon challenges our understanding of how thermonuclear explosions in stars occur. We thought we knew this, but this discovery proposes a totally new way to achieve them,” he adds.
Micronovae are extremely powerful events, but are small on astronomical scales; they are much less energetic than the stellar explosions known as novae, which astronomers have known about for centuries.
Both types of explosions occur on white dwarfs - dead stars with a mass about that of our Sun, but as small as Earth.
A white dwarf in a two-star system can steal material, mostly hydrogen, from its companion star if they are close enough together. As this gas falls onto the very hot surface of the white dwarf star, it triggers the hydrogen atoms to fuse into helium explosively. In novae, these thermonuclear explosions occur over the entire stellar surface.
The research has been published in the journal Nature.