TESS data from 2018 to 2026 show repeat events for 36 of 164 K2 single-transit candidates, give one period for 6 systems, and limit TOI-5560.01 (EPIC 211924561) to 70.25 or 140.49 days

LaCourse and Jacobs (2018) listed 164 single transit and eclipse events in K2 Campaigns 0 to 14. We searched 511 TESS sector light curves (SPOC, TESS-SPOC, QLP and our own TESScut photometry, sectors 2 to 98 and a 2026 segment) and all K2 campaigns of the 163 stars for a second event with the K2 shape. We used a local matched filter with an empirical noise scale, sensitivity intervals, 5,090 injections (99.9 % recovered where expected SNR is 10 or more) and a sign-flipped control. 35 candidates show a shape-matched TESS repeat at SNR 15 or more (49 dips against 2 control brightenings). Seven more repeat only in later K2 campaigns. With all K2 and TESS coverage, six systems have one allowed period (22.9041, 34.7456, 49.2501, 62.5946, 73.9624 and 182.2453 d). All six have companions larger than 2 Jupiter radii and are probably eclipsing binaries. For EPIC 211924561 (TOI-5560.01, depth 0.23 %), events in K2 C5, K2 C16, TESS S46 and S72 leave only 140.494 or 70.247 d. VSX periods of 10 recovered eclipsing stars are excluded by the data. A small-companion duration model predicts 20.6 secure repeats for events deeper than 5 % and we see 15 (p = 0.027). This agrees with stellar companions. TESS removes a median 17 % of the log-period range for 76 sensitive non-detections. Limitations: no pixel-level vetting of each TESS event, approximate dilution, a strictly periodic solver, and a secure threshold chosen after the control. Code, aggregate results, input hashes and a retrieval script are included. Raw light curves stay at MAST.

K2 · TESS · single transit · long-period planets · eclipsing binaries · orbital period · TOI-5560 · EPIC 211924561 · injection-recovery · VSX