JWST Reveals Salty Sodium Chloride Clouds on the Famous Pink Planet
Summary: On June 21, 2026, JWST observations of an exoplanet discovered in 2013 (25 times Jupiters mass, orbiting a sun-like star) revealed sodium chloride clouds for the first time, solving the mystery of the Pink Planets coloration.
In 2013, astronomers discovered an exoplanet designated GJ 504b orbiting a sun-like star roughly 57 light-years from Earth. With a mass approximately 25 times that of Jupiter, the object displays a rare pink hue that earned it the popular nickname the Pink Planet. It also ranks among the coldest companions ever detected by ground-based instruments.
A team led by Aneesh Baburaj of Northwestern University recently used the James Webb Space Telescope (JWST) to observe GJ 504b in infrared light. In just a couple of hours, JWST gathered enough photons to construct the first detailed spectrum of the object. The analysis revealed sodium chloride (NaCl) clouds in its atmosphere, along with water vapor, methane, and ammonia.
This is the first time we have found that salt clouds are critical to explaining the spectrum of an object, Baburaj said. Theoretical models had long predicted that cold giant planets could form salt cloud layers, but direct observational evidence remained elusive. The JWST data confirm that sodium chloride clouds effectively mask molecular signatures in the deeper atmosphere — precisely the mechanism responsible for the Pink Planets distinctive coloration.