NGTS and WASP photometric recovery of a single-transit candidate from TESS
Hellier, Coel; Jackman, James A. G.; Wheatley, Peter J.; Bayliss, Daniel; Moyano, Maximiliano; Günther, Maximilian N.; Casewell, Sarah L.; Gill, Samuel; Goad, Michael R.; Anderson, David R.; Burleigh, Matthew R.; Jenkins, James S.; Lendl, Monika; McCormac, James; Udry, Stéphane; West, Richard G.; Smith, Alexis M. S.; Bryant, Edward M.; Bouchy, François; Chaushev, Alexander; Nielsen, Louise D.; Raynard, Liam; Pollacco, Don; Acton, Jack S.; Tilbrook, Rosanna H.; Turner, Oliver; Collier Cameron, Andrew; Cooke, Benjamin F.; Belardi, Claudia
United Kingdom, Switzerland, Austria, Germany, United States, Chile
Abstract
The Transiting Exoplanet Survey Satellite (TESS) produces a large number of single-transit event candidates, since the mission monitors most stars for only ∼27 d. Such candidates correspond to long-period planets or eclipsing binaries. Using the TESS Sector 1 full-frame images, we identified a 7750 ppm single-transit event with a duration of 7 h around the moderately evolved F-dwarf star TIC-238855958 (Tmag = 10.23, Teff = 6280 ± 85 K). Using archival WASP photometry we constrained the true orbital period to one of three possible values. We detected a subsequent transit-event with NGTS, which revealed the orbital period to be 38.20 d. Radial velocity measurements from the CORALIE Spectrograph show the secondary object has a mass of M2 = 0.148 ± 0.003 M⊙, indicating this system is an F-M eclipsing binary. The radius of the M-dwarf companion is R2 = 0.171 ± 0.003 R⊙, making this one of the most well characterized stars in this mass regime. We find that its radius is 2.3σ lower than expected from stellar evolution models.