Light curves from TESS Sector 2 described in Sects. 2 and 4.1.1. Unbinned data are shown as grey points, and data in 30 min bins are shown as black circles. The best fitting transit model for the system is shown in black; the associated parameter values are shown in Tables 3 and 4. The positions of the transits are marked with lines coloured according to the legend. The photometry before and after the mid-sector gap are shown in the top and bottom panels, respectively. As the first transit of planet f (thick teal line) occurred precisely between the two transits of the similarly sized planet g (period of 20.71 d - red lines), the three transits were originally thought to have arisen due to a single planet, which was originally designated TOI-178.02 with a period of 10.35 d (see Sect. 2).