NGTS and WASP photometric recovery of a single-transit candidate from TESS

Abstract

The Transiting Exoplanet Survey Satellite (TESS ) produces a large number of singletransit event candidates, since the mission monitors most stars for only ∼27 days. 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 hours around the moderately evolved F-dwarf star TIC-238855958 (Tmag=10.23, T eff =6280±85 K). Using archival WASP photometry we constrained the true orbital period to one of three possible values. We detected a subsequent transitevent 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 M 2 = 0.148 ± 0.003 M , indicating this system is an F-M eclipsing binary. The radius of the M-dwarf companion is R 2 = 0.171 ± 0.003 R , making this one of the most well characterised stars in this mass regime. We find that its radius is 2.3-σ lower than expected from stellar evolution models.

A long-period (P = 61.8 d) M5V dwarf eclipsing a Sun-like star from TESS and NGTS

“…We conducted a systematic search for single-transit events in lightcurves produced from TESS full-frame images (Jenkins et al 2016) as described by Gill et al (2020). The G-type Solar analogue TIC-231005575 was observed with Camera 3 during sectors 2 and 3 (2018 Aug 22 -2018 Oct 18).…”

“…We crossmatched TIC-231005575 with archival data from the Wide-Angle Search for Planets (WASP; Pollacco et al 2006). Unlike TIC-238855958 (Gill et al 2020), there are no photometric data points for TIC-231005575 in the WASP archive despite having observations for stars of similar magnitudes within 3 arc minutes of TIC-231005575; the reasons for this are unclear.…”

“…Around M-stars, planets at these periods may be in the temperate zone and longer period eclipsing binaries are of 2.7886 ± 0.0267 TESS [T] 12.061 ± 0.010 APASS9 [B] 13.289 ± 0.010 APASS9 [V] 12.625 ± 0.030 APASS9 [g'] 12.903 ± 0.038 APASS9 [r'] 12.442 ± 0.036 APASS9 [i'] 12.228 ± 0.037 2MASS [J 11.293 ± 0.040] 2MASS [H] 10.981 ± 0.040 2MASS [K ] 11.037 ± 0.040 interest as they are less likely to be under the influence of strong tidal interactions. Recently it has been shown that recovery of TESS single transits is possible and practical for specialised facilities (Gill et al 2020;Lendl et al 2019). This is allowing us to begin probing more of these longer period planets and stellar binaries using facilities such as the Next Generation Transit Survey (NGTS, Wheatley et al 2018).…”

CHEOPS observations of TESS primary mission monotransits

“…We simulate a suite of photometric and spectroscopic observations using the Next Generation Transit Survey at Paranal (NGTS, Wheatley et al 2018) and CORALIE on the Euler 1.2 m telescope (Queloz et al 2000) respectively. For photometric observations we simulate a stare campaign observing the target for a set amount of days using all night time hours as employed by Gill et al (2019). For spectroscopy we simulate one data point taken every 3 days for a set amount of time.…”

NGTS J214358.5−380102 – NGTS discovery of the most eccentric known eclipsing M-dwarf binary system

“…NGTS has already identified one of only three field-age (<1 Gyr) late M-dwarf binaries (Casewell et al 2018) which provides a valuable addition to the mass-radius relationship for M-dwarfs. NGTS has also identified many candidate eclipsing binary systems covering a wide range of parameter space which continue to be investigated (e.g Gill et al 2019, Lendl et al 2019.…”