Astronomers have used the James Webb Space Telescope to reveal salt clouds in the atmosphere of GJ 504 b, a cold planetary-mass companion known as the Pink Planet.
The findings, published June 18 in the Astronomical Journal, mark the first direct evidence of salt clouds on such a cold object. Led by Northwestern University's Aneesh Baburaj, the team obtained the object's spectrum in just two hours of observation.
GJ 504 b, discovered in 2013 and located 57 light-years from Earth, has a mass about 25 times that of Jupiter and a temperature of roughly 550 degrees Fahrenheit. Researchers had long struggled to explain its pinkish haze and atmospheric properties.
The spectrum showed water vapor, methane, carbon dioxide and ammonia. Models only matched observations when salt clouds were included, confirming predictions made more than 15 years ago.
Baburaj noted that the results also suggest possible metal enrichment and that the methods could aid studies of other faint, cold worlds.