The model fit on the other hand suggested a mass of 1 MJup and an age of 20 Myrs, due to a low surface gravity.

These newer ATMO2020++ models fit better to the spectrum of WISE 0359−5401 and produce more realistic surface gravity, age, mass and metallicity.

WISE 0359−5401 according to the newer models has a solar metallicity, a surface gravity of log g = 4.5, an age of about 2.5 billion years and a mass of about 14 MJup.

[4] Both old and new models produce a better fit with an atmosphere that does not contain the molecule phosphine (PH3), which was previously suspected to exist in cold brown dwarfs.

[4] Another work used atmospheric retrieval to analyse the JWST spectrum and obtained mixing ratios for the major absorbers H2O, CH4, CO, CO2, NH3, PH3 and hydrogen sulfide (H2S).

This work found signs of vigorous vertical mixing and was able to constrain the carbon to oxygen ratio to (C/O)atm = 0.548 ±0.002.