7
Figure 2. Color magnitude diagrams using JWST filters expected to be commonly used for brown dwarfs.
Grey dots represent the photometric sample from Leggett et al. (2021) converted on to the JWST system.
Green squares represent recently published JWST data. Yellow circles and stars indicate the observed and
synthesized colors, respectively, for the 260 K Y dwarf WISE 0855. Black lines are ATMO2020++ model
sequences with parameters as given in the upper legend. Purple lines are disequilibrium chemistry sequences
from Lacy & Burrows (2023), for 250 ≤ T K ≤ 350, and other parameters as given in the lower legend.
eff
See text for further discussion. WISE 0535 (WISE J053516.80-750024.9), like WISE 1828, is an unresolved
apparently overluminous system (e.g. Leggett et al. 2021).