Central source luminosity profiles $L_{\star }+L_{\mathrm{acc}}^{\mathrm{UV}}$ used in time-dependent radiation transfer for the outer passive disk and fully active disk models (blue lines; the vertical axis on the right). The observed light curve of FU Ori, incorporating data from Hoffleit (1939), Wachmann (1954), Mendoza (1968), Kolotilov & Petrov (1985), Kenyon et al. (1988, 2000), Green et al. (2006), Siwak et al. (2018), Jayasinghe et al. (2018), and additional data for 2017–2023 (t >  80 yr) obtained from the Schmidt and RC80 telescopes at Konkoly Observatory is shown by dots.