roughbarked said:
ABC Science link
New type of cosmic explosion called a ‘micronova’ discovered by astronomers.
“We have discovered and identified for the first time what we are calling a micronova,” said Simone Scaringi, an astronomer at Durham University in the UK.
“What’s incredible is that these bursts are very fast; they only last 10 hours to half a day and then are gone,” said Dr Scaringi, who led the discovery.
These fleeting flashes appear to just happen at the poles of some types of magnetised stars, rather than right across the star.
Dr Scaringi said the discovery, reported today in the journal Nature, challenged our understanding of how thermonuclear explosions happened in some stars.
“While trawling through data from NASA’s Transiting Exoplanet Survey Satellite (TESS), Dr Scaringi and his colleagues detected a series of very fast, rapid bursts of energy coming from a white dwarf star.
“While these bursts were a million times less powerful than novae explosions, they still packed a punch, burning through 20,000 trillion tonnes of material – roughly the equivalent of a hefty asteroid – in just hours.
“Soon after, the team found another white dwarf in the TESS data doing the same thing, and a third white dwarf was confirmed with observations using the European Southern Observatory’s Very Large Telescope in Chile.
“When white dwarf stars, which are about the size of Earth, are close to another star, they suck hydrogen gas off their companion. The gas builds up on the surface of the white dwarf, causing the star to heat up, triggering a runaway thermonuclear reaction.”
So what we’re seeing here is a small (on the stellar scale) natural thermonuclear explosion. I wonder how many mega-tonnes?
“3.5×10^38 erg, 5.2×10^38 erg and 1.2×10^39 erg”
3.5×10^38 erg = 8,365,200,764,818,450 Megaton
And they call it a micronova.