2056015

Target RA (J2000): 157.935440 and deg Target Dec (J2000): 0.93757 and deg Gaia GMag: 11.349 Programme ID: CH_PR230008 PI of observing programme: Jiang Title of programme: : Bridging CHEOPS and Twinkle: forming long TTV baselines for the multi-planet system K2-266 Abstract: The measuring of transit timing variations (TTVs) allows one to explore the dynamical interactions of planets within a system shedding light on the properties of these bodies. Here propose to observe the transits of two planets in the K2-266 system K2-266d and K2-266e in order to more robustly constrain the previously reported TTVs. These data will allow us to obtain much more precise mass and orbital parameters of this unique system. TESS has observed the system already adding to the time baseline relative to the original K2 observations but the TESS data are not accurate enough to distinguish between competing models. However as discussed in the scientific justification of this proposal the CHEOPS data proposed here is able to distinguish between different models with small differences in the system parameters. The ability to precisely distinguish between competing models means the CHEOPS data will provide a high precision measurement and bring a large impact into the study of this astronomically important planet system. Furthermore as members of the Twinkle Space Mission’s exoplanet TTV Working Group we aim to observe this system with Twinkle in the future. While the data proposed for here is valuable in its own right combining data from both these small low-Earth orbit satellites over a long baseline will yield better results than using either one alone. [truncated! Please see actual data for full text]