A BLS search of 123 M dwarfs in TESS Sector 107 2-min light curves recovered 2 of 6 known TOIs and found no credible new planet candidate at periods of 0.5-13 days

Question: Do the TESS Sector 107 2-minute light curves of bright M dwarfs contain transit signals that the TOI process has not reported? Method: We selected stars with Teff < 3700 K, radius < 0.55 R_sun and Tmag < 13 from the FITS headers of 5,043 of the 12,998 Sector 107 SPOC light curves. We searched 123 of the 228 selected stars (Tmag 9.05-12.65). We removed the trend with an 18 h running median, binned the data to 10 min and ran a box least squares (BLS) search for periods of 0.5-13 d. We kept 2 signals for each star. We used light-curve-only tests: SNR, SDE, number of events, single-event dominance, odd/even depth, secondary depth, maximum circular-orbit duration and a post-hoc test for events at data-segment edges. We compared each signal with the ExoFOP TOI catalog and the SPOC Sector 107 TCE list. Result: 4 of 246 signals passed all tests. 2 are known planets, TOI-7716.01 and TOI-256.02 (LHS 1140 c). 1 is a known SPOC TCE on TIC 65347864: its dips repeat every 0.320 d and SPOC finds 3 unrelated periods, so it is most likely a variable star or a blended binary. 1 signal on TIC 43375040 (P = 10.72 d, depth 3.8 ppt, SNR 8.5) has no TOI or TCE match, but it has only 2 partial events, one near the end of the sector, and a long duration. We do not claim it as a candidate. The edge test removed 2 more unmatched signals; their events are at segment edges. The search found a BLS signal at the period of 4 of 6 known TOIs, and 2 of 6 passed vetting. Limitations: one sector; 123 stars only; no centroid or pixel tests; only 2 signals for each star; low sensitivity below about 1 ppt and for periods with 2 events. The package contains the code, the binned light curves, all signal metrics and the steps to reproduce the work.

TESS · Sector 107 · M dwarfs · transit search · box least squares · exoplanets · null result · TOI recovery · vetting · LHS 1140