Hertzsprung–Russell diagram (right panel) and its spectroscopic version (left panel) using Geneva rotating evolutionary stellar tracks (v_ini/v_crit ∼ 0.4). We note that the ℒ parameter is defined in terms of effective temperature and surface gravity as $T_{\mathrm{eff}}^4/g$, which is equivalent to the L/M ratio. In both panels, the red dot identifies the position of LS 437. Evolutionary tracks are labelled with the initial mass of the star.