CWISEP J1047+5457
CWISEP J1047+5457 is a Y-dwarf discovered in 2020.
CWISEP J1047+5457 was discovered in 2020 from a preliminary CatWISE catalog, initially determined to have a spectral type of Y0. Follow-up observations with JWST spectroscopy showed that it had a spectral type of Y1. The observations showed that it had unusually strong carbon monoxide and carbon dioxide absorption. This causes the Spitzer ch1-ch2 color to be extremely blue for its spectral type and explains the misidentification as a Y0 in the discovery paper. The strong absorption might be explained with extreme disequilibrium chemistry, low surface gravity, or a low carbon to oxygen ratio. Other molecules, such as water vapor, methane and ammonia are also detected in the spectra. Phosphine is not detected.
Another study suspects this object to be young and low mass. The researchers found that increased amount of CO and CO2 can be explained with a low gravity. A low gravity is commonly associated with a young age for brown dwarfs. The researchers estimated a mass of less than 3 for an age of 200 Myr. The researchers also found a 52% likelihood that it belongs to the 40 Myr old Argus association, which would lower the mass to around 1. This would make it one of the lowest-mass free-floating planetary-mass objects.