TESS sector 107 shows second transits of two single-transit CTOIs; the 9 Earth-radius candidate TIC 60479865 has 39 possible periods, 95 % of the probability at 27.6-89.9 d (eccentric orbit prior)

We searched the TESS sector 107 SPOC 2-minute light curves of 12 996 stars for single transit-like events with durations of 1 h to 14 h. We masked the transits of known TOIs and SPOC TCEs. Automatic cuts kept 13 of 1649 events, and we examined each of the 13 events. Two events are second transits of community TOIs (CTOIs) that had one transit and no period. TIC 60479865 (CTOI 60479865.01) is a K dwarf (Teff 5042 K, Tmag 11.2). Its transits in sectors 33 and 107 are 2066.768 d apart. A joint fit gives a depth of 10.8 ppt, a duration of 6.06 h and a radius of 9.0 +- 0.6 Earth radii. The difference image puts the sector 107 signal on the target. The TESS data of sectors 6, 33, 87 and 107 remove 4094 of the 4133 periods P = 2066.768 d / n with P >= 0.5 d. With an eccentric orbit prior and a P^-5/3 period prior, 95 % of the probability is in the periods from 27.6 d to 89.9 d. The Gaia DR3 radial-velocity scatter limits the mass to less than 80 Jupiter masses for aliases that hold 99 % of the probability. We give the predicted transit times of all 39 aliases in TESS sectors 108 to 110. Transits after 2026-10-24 will test aliases that hold 82 % to 87 % of the probability. HD 11506 (CTOI 266680498.01) has a 0.68 ppt, 3.2 h event in sectors 30 and 107 (3.8 Earth radii); 43 periods of 25.9 d or more remain. This candidate needs more checks. The other 11 events are an eclipsing binary, a known TOI, signals from other stars, instrument artifacts, stellar variability or noise, and one marginal event. Injection-recovery tests with 9000 transits give a recovery fraction of 0.63 to 0.68 for an expected SNR of 30 or more. A different SCI search of sector 107 (sci:sha256:58e512dfb29aef9ce3a0320ce7332b1e53947e8c79ee036d1626e9b6a418b9d1) detected the TIC 60479865 transit at SNR 18.9, but its cuts removed it. One of these cuts responded to a slow flux decrease at the end of the sector, not to a second transit. Only the HD 11506 event passes the cuts of both searches. Limits: the radius uses the TIC stellar radius, and a companion star (Gaia RUWE 1.64) could make the true radius larger. The alias probabilities depend on the priors. We searched sector 107 only.

TESS · single transit · duotransit · period aliases · TIC 60479865 · CTOI 60479865.01 · HD 11506 · TIC 266680498 · CTOI 266680498.01 · TESS sector 107 · Gaia DR3 radial velocity · transit timing predictions · injection-recovery · K dwarf · warm Saturn · stellar rotation · community TOI · monotransit search · search comparison