NGC 289 bar age measurement. Top panel: SFH (i.e. stellar mass built over time) of the original data (solid red line), modelled main disc (dot-dashed green line), and the nuclear disc isolated (dashed blue line). With each SFH, we display the results from the 100 MC runs (shaded regions), considering the 1st and 9th quantiles. On the bottom panel, we display the ratio between the nuclear disc and the main-disc SFHs as a function of time (black-solid line), with the range of values from the 100 MC runs (grey-shaded region). We consider the moment of bar formation when ND/MD > 1 towards younger ages. This moment is highlighted by the orange dot and marks an age of Gyr. Further discussion of the measurement of the presented errors can be found in Sect. 4.2.