A faint object discovered in 2013, dubbed the Pink Planet, has yielded its first spectrum thanks to the James Webb Space Telescope (JWST). The observations mark a breakthrough for a target too dim for ground-based instruments to analyze.
Advanced processing of JWST data provided some of the first direct evidence for salt clouds — specifically sodium chloride — in a cold object’s atmosphere. The chemical signature suggests a composition more akin to a gas giant than a typical star.
Astronomers refer to the object as a 'planetary-mass companion,' as its exact nature remains ambiguous: it could be a giant planet or a brown dwarf. The new spectrum helps narrow down its temperature and chemical makeup but does not settle the classification debate.
The study adds a fresh data point for models of substellar atmospheres. Salt clouds have been theorized for hot exoplanets and cool brown dwarfs, but direct confirmation has been elusive until now.
A caveat: the Pink Planet’s spectrum is still limited to a single epoch. Without repeated observations, it is unclear whether the salt clouds are persistent or transient, leaving room for alternative interpretations of the chemistry.