2025AJ....169..186D

We present new color-ϒ_* (mass-to-light ratio) models to convert Wide-field Infrared Survey Explorer W1 fluxes into stellar masses. We outline a range of possible star formation histories and chemical evolution scenarios to explore the confidence limits of stellar population models on the value of ϒ_*. We conclude that the greatest uncertainties (around 0.1 dex in ϒ_*) occur for the bluest galaxies with the strongest variation in recent star formation. For high-mass galaxies, the greatest uncertainty arises from the proper treatment of bulge-disk separation in which to apply different ϒ_* relations appropriate for those differing underlying stellar populations. We compare our deduced stellar masses with those deduced from Spitzer Space Telescope 3.6 μm fluxes and stellar mass estimates in the literature using optical photometry and different ϒ_* modeling. We find the correspondence to be excellent, arguing that rest-frame near-IR photometry is still more advantageous than other wavelengths.