NASA's SPHEREx Telescope Reveals Chemically Rich Atmospheres in Thousands of Free-Floating Brown Dwarfs

NASA’s SPHEREx space telescope is uncovering thousands of free-floating brown dwarfs, which are celestial objects that blur the line between stars and giant planets. A new study published in The Astrophysical Journal shows that these dark worlds have chemically rich atmospheres. The research team analyzed SPHEREx observations of 37 nearby brown dwarfs with temperatures ranging from about 4,000 to minus 10 degrees Fahrenheit.

By measuring brightness across 102 different colors using infrared light, the telescope revealed atmospheric water, carbon dioxide, carbon monoxide, and methane. While brown dwarfs form like stars from collapsing gas clouds, they lack the mass needed to sustain hydrogen fusion. Instead, they drift alone in darkness. Ground-based telescopes miss these specific deep red and infrared wavelengths because water in Earth's atmosphere absorbs them.

Only a few dozen brown dwarfs have previously been studied in detail with space telescopes. Scientists are now in the process of analyzing thousands more captured by SPHEREx to test theoretical models, though current models struggle to match data during cloudy atmospheric transitions.