Ṁ-luminosity relations as determined by Beasor et al. (2020). The coloured symbols represent the (L_bol, Ṁ_SED)-values for four open clusters as derived by Beasor & Davies (2016), Beasor et al. (2020); error bars indicate their most conservative error estimates. The straight lines in both panels show the individual straight-line fits to each relation log(Ṁ_SED/M_⊙ yr⁻¹) = a + b log(L_bol/L_⊙) for all clusters in the sample. In the left panel, the dashed lines show the Ṁ-L_bol relation using the values for the offset and slope as given in Table 4 of Beasor et al. (2020); the full lines in the right panel show the fits to the Ṁ-L_bol relation once the gradient is fixed to b = 4.8, following Eq. 4 of Beasor et al. (2020) and using the values for the initial mass as given in Table 1 of Beasor et al. (2020). The red dotted line in the left panel shows the fit to RSGC1 for an intercept a = -53; see footnote 7. The red dashed-triple dotted lin in the right panel shows the fit to RSGC1 following Eq. (E.1).