The NASA Transiting Exoplanet Survey Satellite ( TESS ) mission will discover thousands of candidate transiting exoplanets .
Due to the mission configuration , 74 % of the area to be observed by TESS will only have an observational baseline of 27 days .
For those planets with orbital periods longer than 13.5 days , TESS can only capture one or two transits , which means the true ephemerides will be difficult to determine from TESS data alone .
Follow-up observations of the transits of these candidates to efficiently confirm and characterize them will require precise ephemerides .
We explore the value of using existing ground-based wide-field photometric surveys to constrain the ephemerides of the TESS single-transit candidates .
The Kilodegree Extremely Little Transit ( KELT ) survey has a long observation baseline ( up to eight years ) and monitors fields that largely overlap with the TESS footprint , and also observes stars of similar brightness .
We insert simulated TESS-detected single transits into KELT light curves , and evaluate how well their orbital periods can be recovered .
We find that KELT photometry can be used to confirm ephemerides with high accuracy for planets of Saturn size or larger with orbital periods as long as a year , and therefore span a wide range of planet equilibrium temperatures .
In a large fraction of the sky we recover 30 % to 50 % of the warm Jupiter systems ( planet radius of 0.9 to 1.1 R _ { J } and 13.5 < P < 50 days ) , 50 % to 80 % of the warm inflated Jupiters ( planet radius of 1.1 to 2 R _ { J } ) , 5 % to 18 % of the temperate Jupiters ( 50 < P < 300 days ) , 10 % to 50 % of the temperate inflated Jupiters and 10 % to 30 % of the warm Saturns ( planet radius of 0.5 to 0.9 R _ { J } and 13.5 < P < 50 days ) .
The resulting periods and ephemerides of the signals can then be used by follow-up teams , whether part of the TESS mission or community-organized TESS follow-up , to plan and coordinate follow-up observations to confirm candidates as planets , eclipsing binaries , or other false positives , as well as to conduct detailed transit observations with facilities like JWST or HST .