Comparison of temperature and abundance constraints. Left panel : temperature profiles of Luhman 16A and B, retrieved with the chemical disequilibrium model described in Sect. 2.2.3. Luhman 16A displays a heating of ~100 K near the photosphere, which is indicated by the shaded regions in the left side of the panel. Middle panel : mixing and chemical reaction timescales as functions of pressure. The intersection where vertical mixing becomes more efficient than the CO-CH₄ reaction is indicated by a horizontal bar. The higher K_zz for Luhman 16A is visible from its reduced mixing timescale. Right panels : cutouts of the chemical abundance profiles between 0.06 and 30 bar. From top to bottom : chemical disequilibrium and free-chemistry abundances from the K-band analysis of this work, and the CRIRES⁺ J-band constraints presented in de Regt et al. (2025b). The envelopes and error bars in all panels show the 68% credible region.