V- and K-band light curves of the pulsating RSG surrounded by a dust shell. The parameter τ₀ sets the optical depth at the beginning of the pulsation cycle (ϕ = 0). The light dotted lines indicate regions outside the MARCS grid (too low T_eff) that do not allow us to make photometric estimates. For better visualization, two full pulsation cycles are shown. The light, horizontal lines show the time-averaged magnitudes. For comparison, the phase-folded, visual light curve of VX Sgr is shown as well, with data taken between JD = 2640000 and 2644000, and assuming a period of 747 days.