2.1.

TESS photometry TOI-2147 was observed in eight TESS sectors (14, 19, 20, 26, 40, 47, 53, 60, 73, 74) at different cadences (30 min, 10 min, and 2 min).

TOI-6019 was observed in Sector 57 and 84 with a 2-minute cadence.

Transit events were detected by the Quick Look Pipeline (QLP, Huang et al. 2020a,b; Kunimoto et al. 2021, 2022) and the TESS Science Processing Operation Center pipeline (SPOC Jenkins et al. 2016, 2020).

We used the lightkurve package (Lightkurve Collaboration et al. 2018) to download the TESS-SPOC High-Level Science Product (Caldwell et al. 2020) light curves.

For our analysis, we used the presearch data conditioning simple aperture photometry (PDCSAP, Smith et al. 2012; Stumpe et al. 2012, 2014) light curves, which correct the simple aperture photometry (SAP) for various instruArticle number, page 2 of 14
mental and systematic effects.

The reported orbital periods and depths of the transit events by the TESS team on ExoFOP are 26.2 days and 5593 ppm for TOI-2147.01 and 14.55 days and 3223 ppm for TOI-6019.01.

The light curves are shown in Figure 1.
2.2.

Ground-based photometric follow-up The TESS pixel scale is ∼21′′ pixel−1 and photometric apertures typically extend out to roughly 1 arcminute, generally causing multiple stars to blend in the TESS photometric aperture.

To determine the true source of the TESS detection, we acquired ground-based time-series follow-up photometry of the fields around TOI-2147 and TOI-6019 as part of the TESS Followup Observing Program (TFOP; Collins 2019)1.

The on-target follow-up light curves are also used to place constraints on the transit depth and the TESS ephemeris.

Multiband observations place limits on transit depth chromaticity.

We used the TESS Transit Finder, a customized version of the Tapir software package (Jensen 2013), to schedule our transit observations.
2.2.1.

LCOGT We observed a transit egress window of TOI-2147.01 in alternating B and Pan-STARRS zs filters on February 14, 2022, from the Las Cumbres Observatory Global Telescope (LCOGT; Brown et al. 2013) 1.0 m network node at Teide Observatory on the island of Tenerife (Teide).

Exposure times were set at 30 s for the B filter and 45 s for the zs filter.

The 1 m telescopes are equipped with a 4096 × 4096 SINISTRO camera having an image scale of 0′′.389 per pixel, resulting in a 26′ × 26′ field of view.

The images were calibrated by the standard LCOGT BANZAI pipeline (McCully et al. 2018), and differential photometric data were extracted using AstroImageJ (Collins et al. 2017).

We used circular photometric apertures with radius 4′′.5, which excluded all of the flux from the nearest known neighbor in the Gaia DR3 catalog that is bright enough to possibly be the source of the TESS TOI-2147 transit event (Gaia DR3 1146601236892702720), which is 24′′.4 east of TOI-2147.

Transit egress with consistent depth was detected in the target star apertures in both filter bands, thus confirming an achromatic transit-like event on-target.

The light curve data are included in the joint modeling analyses described in Section 4.
2.2.2.

New Mexico Skies-T19 We observed the egress of TOI-2147.01 on March 13, 2022, in the Exo filter using the remote 0.43 m iTelescope located during the time of observation at New Mexico Skies2.

Imaging was done with an SBIG STX-16803 CCD camera, which has an array of 4096 × 4096 pixels with a pixel size of 9 µm x 9 µm.

Weather conditions were good with clear skies.

During the imaging session, the wind speed reached peaks up to 16.1 km/h, and the seeing was measured between 1.3 and 2.5 FWHM arcseconds.