Title of programme: Photometric Confirmation of The Brightest-Host Transiting Habitable Zone Terrestrial Exoplanet
Abstract: We propose to use CHEOPS photometry to confirm the existence of the Transiting Exoplanet Survey Satellite (TESS) planet candidate TOI4353.01 (TIC176797879). This object is nominally a terrestrial-size exoplanet with two transits separated by 718 days in the TESS photometry. However, one transit occurs near the peak of a large spike in background flux. Because of the ease of matching a single valid transit to transit-like noise, it is difficult to establish with high confidence that this first transit event is real, though we take several measures to do so. By searching for another transit with CHEOPS, we can test the existence of a transiting candidate around this star. Based on the transit duration and a priori likelihood of transit, the true period is very unlikely to be 718 days, and instead is more likely to be 25-60 days. If the signal is confirmed to be real by the proposed observations, it would pave the way for future followup. Such a signal would represent a terrestrial planet candidate with an overwhelming probability of being in the optimistic habitable zone (OHZ) and potential for future mass measurement and even transmission spectroscopy thanks to its bright (for an M star) host. Because of the great rarity of terrestrial OHZ exoplanets and the difficulty of discovering more with TESS due to its short sectors, followup of candidates like this one is of critical importance.
Temporal Coverage
2022-10-10T12:58:00Z / 2022-10-11T05:54:00Z
Version
3.0
Mission Description
CHEOPS (Benz et al., https://doi.org/10.1007/s10686-020-09679-4) is a European Space Agency (ESA) mission in partnership with Switzerland with important contributions to the payload and the ground segment from Austria, Belgium, France, Germany, Hungary, Italy, Portugal, Spain, Sweden and the United Kingdom.
The satellite has a single payload comprising an ultra-high precision photometer covering the 330 - 1100 nm wavelength range in a single photometric band. Observations are made as part of the Guaranteed Time Observing Programme that is formulated by the CHEOPS Science Team, and the Guest Observers Programme through which the Community at large can apply for CHEOPS time.
