NASA’s SPHEREx all-sky mapper has recorded detailed infrared spectra of 33 brown dwarfs between 7 and 100 light-years away, objects too small to burn hydrogen like true stars. Across its 102 colour channels from 0.75 to 5 microns, the team led by Zafar Rustamkulov of Caltech and JPL saw water vapour, methane and carbon monoxide, and tracked how carbon switches from carbon monoxide to methane as these bodies cool below about 1,000 K. None of five leading atmosphere models matched every detail, with some getting sizes wrong by 20 to 50 per cent. The study appears in The Astrophysical Journal Letters. Our take: SPHEREx’s survey should soon add thousands more, a goldmine for understanding cold giant planets too.
33nearby brown dwarfs measured
102colour channels across the whole sky
7–100 lydistance range of the sample