James Webb Space Telescope finds salt clouds surround one of the coldest objects ever studied
Discovered in 2013, the Pink Planet orbits a sun-like star located 57 light-years from Earth. At roughly 25 times the mass of Jupiter, it sits near the fuzzy boundary between giant planets and brown dwarfs. So, astronomers refer to it as a “planetary-mass companion,” meaning that it’s a planet-sized object orbiting a star. Illustration courtesy of NASA/Goddard Space Flight Center
Northwestern University-led astronomers have discovered salty skies surrounding the universe’s famous “Pink Planet.”
For more than a decade, the ancient, rosy hazed world kept astronomers guessing. One of the coldest known planetary-mass companions ever directly imaged, the elusive object is too faint for astronomers to dissect its light from Earth. But new observations from the James Webb Space Telescope (JWST) reveal an atmosphere filled with exotic chemistry — and salty clouds unlike anything seen before.
The observations provide some of the first direct evidence for salt clouds in a cold object’s atmosphere, a phenomenon scientists theorized more than 15 years ago. The discovery also marks an important step toward studying increasingly cold objects, which are too dim to examine with ground-based telescopes.
The study was published in the Astronomical Journal.
“The Pink Planet is the coldest companion ever discovered using ground-based instruments,” said Northwestern’s Aneesh Baburaj, who led the study. “Many teams all around the world performed follow-up observations to study its light, but it was too faint for ground-based instruments. That made it a perfect target for JWST. When we finally obtained its spectrum, it immediately looked interesting. But once we started digging deeper into the data, we realized it was not like anything we have analyzed before.”
An expert on exoplanets, Baburaj is a postdoctoral associate at Northwestern’s Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA). This work was conducted in collaboration with scientists at the Space Telescope Science Institute (STScI), including Marshall Perrin, who devised the observing program for this object. Perrin is a member of the JWST Telescope Scientist Team, which contributed to the telescope’s design and is responsible for its current day-to-day operations.
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