Durham University: New type of stellar explosion called micronovae discovered

Micronovae may also change our understanding of how eruptions in stars occur.

A micronova is a thermonuclear blast that lasts for just a few hours making them extremely difficult to observe.

These outbursts happen on the surface of certain stars and can each burn through a huge amount of stellar material equivalent to around 3.5 billion Great Pyramids of Giza.

White dwarf
Durham’s researchers led an international team of scientists who saw the phenomenon in three white dwarfs – the remnants of dead stars – as they fed in each case on a companion star.

They say their discovery could lead to more micronovae being found and challenge what we know about how thermonuclear explosions occur in stars.

Micronovae are extremely powerful, but are small on astronomical scales compared to novae and supernovae, which are extremely bright and have been known about for centuries.

There are numerous accounts across history of “new stars” being seen by astronomers which were actually novae.

Both types of explosions occur on white dwarfs, dead stars with a mass similar to that of our Sun, but as small as the Earth in size.

Thermonuclear explosion
White dwarfs can steal material, mostly hydrogen, from their companion stars if they are close enough to them.

As the hydrogen falls on to the very hot surface of the dwarf star its atoms fuse into helium in explosive fashion.

In novae this thermonuclear explosion occurs over the entire surface of the star and the intensely bright light from this blast can be seen for weeks.

Micronovae are similar explosions that are smaller in scale and faster, lasting several hours.

The research team is due to publish a follow-up research paper showing the model used to explain what triggers micronovae.