Whiffy.
An out of this world planet where it rains molten glass and a year only lasts two days also stinks of rotten eggs, according to new research.
American astronomers sniffed out the pungent atmosphere using the James Webb Space Telescope.
The findings, published in the journal Nature, show that the atmosphere of HD 189733 b, a Jupiter-sized gas giant, has small amounts of hydrogen sulphide.
The molecule not only gives off a stench, but also offers scientists new clues about how sulphur, a building block of planets, might influence gas worlds beyond the solar system.
Research leader Dr Guangwei Fu, an astrophysicist at Johns Hopkins University, Baltimore, said: ‘Hydrogen sulphide is a major molecule that we didn’t know was there.
‘We predicted it would be, and we know it’s in Jupiter, but we hadn’t really detected it outside the solar system.
‘We’re not looking for life on this planet because it’s way too hot, but finding hydrogen sulphide is a stepping stone for finding this molecule on other planets and gaining more understanding of how different types of planets form.’
As well as detecting hydrogen sulphide and measuring overall sulphur in HD 189733 b’s atmosphere, Dr Fu’s team also precisely measured the main sources of the planet’s oxygen and carbon – water, carbon dioxide and carbon monoxide.
Dr Fu said: ‘Sulphur is a vital element for building more complex molecules, and – like carbon, nitrogen, oxygen, and phosphate – scientists need to study it more to fully understand how planets are made and what they’re made of.’
Just 64 light-years from Earth, the planet is about 13 times closer to its star than Mercury is to the Sun, and takes only about two Earth days to complete an orbit.
It has inferno-like temperatures of 927 degrees Celsius and is notorious for vicious weather, including raining glass that blows sideways on 5,000mph winds.
Dr Fu says HD 189733 b is the nearest ‘hot Jupiter’ astronomers can observe passing in front of its star, making it a benchmark planet for detailed studies of exoplanetary atmospheres since its discovery in 2005.
The JWST gives scientists yet another new tool to track hydrogen sulphide and measure sulphur and heavy metals outside the solar system, helping them better understand how different types of planet form.
