An explosive collision between two icy giant planets has been discovered, after being spotted on a social media post by an amateur astronomer.
A blaze of light and plumes of dust were created after the two exoplanets (planets that orbit a star outside the solar system) 1,800 light years away from Earth, crashed around a sun-like star.
The bright heat afterglow and dust cloud then moved in front of the star which the planets orbited, and dimmed it over time.
It was the star brightening over a thousand days before the optical fading that was pointed out by an enthusiast on social media, and consequently explored by a team of international astronomers.
The light curve of the star showed the system doubled in brightness at infrared wavelengths some three years before the star started to fade in visible light.
“To be honest, this observation was a complete surprise to me,” Dr Matthew Kenworthy, from Leiden University and co-lead author of a paper that published the findings, said.
He said he knew it was an “unusual event”.
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Over the next two years, a network of professional and amateur astronomers studied the star intensively, including changes in its brightness.
It was named ASASSN-21qj after the network of telescopes that first detected the fading of the star at visible wavelengths.
Colours indicate the energies of the materials involved
“Our calculations and computer models indicate the temperature and size of the glowing material, as well as the amount of time the glow has lasted, is consistent with the collision of two ice giant exoplanets,” Dr Simon Lock, co-lead author from the University…
