Title of programme: Period Measurement of The Brightest-Host Transiting Habitable Zone Terrestrial Exoplanet
Abstract: We propose to use CHEOPS photometry to measure the period of the Transiting Exoplanet Survey Satellite (TESS) planet candidate TOI4353.01 (TIC176797879), initially a duo-transit object that was confirmed with a transit detection in previous CHEOPS observations (priv. comm.). This object is a terrestrial-size exoplanet with three transits, each separated by 718 days (two in TESS, one in CHEOPS). This even separation and minimal phase coverage means that the period still needs to be determined. 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 an alias of that spacing, in the 34-60 day range. This planet is therefore a likely-terrestrial planet candidate in its star’s optimistic habitable zone (OHZ). It has potential for future mass measurement and even transmission spectroscopy thanks to its bright (for an M star) host. In fact, no other OHZ terrestrial has a host star as bright as TOI4353.01. Because of the 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
2023-10-25T18:57:00Z / 2023-10-26T06:29:00Z
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.
