Title of programme: Constraining Refractory Species and Characterising the Stellar Environment of the Inflated hot-Jupiter WASP-17 b
Abstract: In the known population of exoplanets, puffy hot-Jupiters are extremely rare and yet crucial in order to understand planetary formation and evolution. Their large radii coupled with the high S/N ratio achievable thanks to their extended atmospheres, makes them the perfect target for current observational facilities. In this restricted pool of planets, WASP-17b is an ideal case study. With an equilibrium temperature of ~1800 K, this inflated hot-Jupiter is expected to display signatures of metal oxides and hydrides in absorption. However, recent studies showed that the host star, a F6 dwarf, appears to be considerably more active than expected. The ability of stellar spots and faculae to mimic absorption features in a planetary atmosphere or hide them altogether, is one of the most serious obstacles in exoplanet transmission studies. The high-precision photometer aboard CHEOPS is the optimal instrument to monitor the transit of WASP-17b for two main reasons. Being centred at 0.6 µm, the CHEOPS photometer targets specifically the wavelengths where the stellar spectrum peaks and where optical absorbers display strong absorption features. Hence, CHEOPS data is essential to solve the ongoing disputes on this planetary system regarding the activity of the host star and the presence of refractory elements in the atmosphere of the companion planet. At least 11 transits with a very high coverage (>65%) are expected to occur during AO-3, making WASP-17 b an excellent target for CHEOPS.
Temporal Coverage
2023-05-30T12:30:00Z / 2023-05-30T20:44:00Z
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.
