First panel (top): early light curve of AT 2019abn (key as in Fig. 1). Second panel: early temperature evolution of AT 2019abn, assuming no change in dust extinction. Third panel: implied additional dust extinction to that seen at peak, if one assumes a constant temperature of T = 7500 K over this portion of the light curve. Fourth panel: early luminosity evolution of AT 2019abn. Fifth panel (bottom): early radius evolution of AT 2019abn. In the last two panels, the black and grey points represent the different assumptions of constant extinction (E_B − V = 0.85) and constant temperature (T = 7500 K), respectively.