Radius vs. surface gravity as a function of age and effective temperature, based on the BEX Hottest cond03 evolutionary models. The color scale on the right represents the age in Myr. Each colored diamond corresponds to predictions using all datasets (Sect. 5) from each atmospheric model: blue for Exo-REM, green for ATMO (not visible here), red for BT-Settl, and orange for Sonora. The purple line indicates the approximate formation age of the β Pic system.