The James Webb Space Telescope (JWST) was used by astronomers to analyze the atmosphere of a nearby brown dwarf binary called WISE J045853.90+643451.9. For the first time, hydrogen cyanide and acetylene were detected in the atmosphere of a brown dwarf. The WISE J045853.90+643451.9 binary consists of two T-dwarfs with similar atmospheres, located just 30.1 light years away. The observations suggest a cloud-free, molecule-rich atmosphere with methane, carbon dioxide, carbon monoxide, water, and ammonia. The presence of hydrogen cyanide and acetylene indicates disequilibrium chemistry, a unique find in brown dwarfs. This discovery showcases the capability of the MRS to study cold brown dwarfs further.
https://phys.org/news/2025-02-hydrogen-cyanide-acetylene-brown-dwarf.html