2036192

Target RA (J2000): 138.602844 and deg Target Dec (J2000): 52.68636 and deg Gaia GMag: 7.05 Programme ID: CH_PR230028 PI of observing programme: Wilson Title of programme: Hunting for a Transit of a HARPS-N Known Exoplanet Target around a TESS Blend Abstract: Since the birth of the exoplanet field the complementarity of the transit and radial velocity (RV) techniques has been well-utilised with a key example being the transit follow-up of the RV planet HD 209458 b. Importantly the extended observing campaigns of RV instruments can yield detections of longer-period planets that if transiting can give a unique glimpse into a currently observationally rare space see Nu2 Lupi. The HARPS-N Consortium has been conducting a decade-long survey of bright stars that yielded the discovery of the four planet system HD 219134 that was found to be transiting by Spitzer. There are several more long-period candidates that need to be followed-up with transit photometry to try to obtain a planetary radius and density. Due to TESS’s observing strategy it is unlikely to find longer-period bodies and because of the large pixel scale transits may be hidden if there is a close bright stellar contaminant that causes blending. CHEOPS is unique and necessary to search for transits of small RV targets with contaminants that would be too shallow for ground-based instruments. We find one target with a >8 sigma RV signal on a period of 24d whose host star is part of a binary system with a separation of 18. We propose for a modest amount of time to hunt for a transit of a low-mass planet around a TESS blended target that could open up a new avenue for characterisation of Earth-like long-period planets that could open up a new utility for CHEOPS. [truncated! Please see actual data for full text]