CHEOPS: a space telescope for ultra-high precision photometry of exoplanet transits

Abstract

The CHaracterising ExOPlanet Satellite (CHEOPS) is a joint ESA-Switzerland space mission dedicated to search for exoplanet transits by means of ultra-high precision photometry whose launch readiness is expected end 2017. The CHEOPS instrument will be the first space telescope dedicated to search for transits on bright stars already known to host planets. By being able to point at nearly any location on the sky, it will provide the unique capability of determining accurate radii for a subset of those planets for which the mass has already been estimated from ground-based spectroscopic surveys. CHEOPS will also provide precision radii for new planets discovered by the next generation ground-based transits surveys (Neptune-size and smaller). The main science goals of the CHEOPS mission will be to study the structure of exoplanets with radii typically ranging from 1 to 6 Earth radii orbiting bright stars. With an accurate knowledge of masses and radii for an unprecedented sample of planets, CHEOPS will set new constraints on the structure and hence on the formation and evolution of planets in this mass range. To reach its goals CHEOPS will measure photometric signals with a precision of 20 ppm in 6 hours of integration time for a 9th magnitude star. This corresponds to a signal to noise of 5 for a transit of an Earth-sized planet orbiting a solar-sized star (0.9 solar radii). This precision will be achieved by using a single frame-transfer backside illuminated CCD detector cool down at 233K and stabilized within ~10 mK . The CHEOPS optical design is based on a Ritchey-Chretien style telescope with 300 mm effective aperture diameter, which provides a defocussed image of the target star while minimizing straylight using a dedicated field stop and baffle system. As CHEOPS will be in a LEO orbit, straylight suppression is a key point to allow the observation of faint stars. The telescope will be the only payload on a spacecraft platform providing pointing stability of < 8 arcsec rms, power of 60W for instrument operations and downlink transmission of at least 1.2GBit/day. Both CHEOPS paylaod and platform will rely mainly on components with flight heritage. The baseline CHEOPS mission fits within the technical readiness requirements, short development time and the cost envelope defined by ESA in its first call for S-missions. It represents a breakthrough opportunity in furthering our understanding of the formation and evolution of planetary systems.

Statistical modelling of an astro-comb for high-precision radial velocity observation

“…Moreover, the precise radial velocity measurements with LFC are significant for the science of the current and future space missions. With the high precision RV follow-up observation with astro-comb, we can enhance the productivity of the transit missions such as TESS (Ricker et al 2014), CHEOPS (Cessa et al 2017) and PLATO (Rauer et al 2016).…”

The role of time in policymaking: a Bahraini model of higher education competition

“…This exceeds ground-based telescopes; a single Next Generation Transit Survey (NGTS) telescope has a precision of 400 ppm over a 30 minute integration [Bayliss et al, 2022]. The design is an improvement on previous exoplanet satellites, showcased in its similarity and use of CoRoT design [Beck et al, 2017b].…”

ArielRad: the Ariel radiometric model

“…In the past 20 years more than 4000 exoplanets have been detected using space and ground based surveys, and many more are expected to be discovered in the coming years thanks to space missions such as TESS [1], CHEOPS [2], PLATO [3] and GAIA [4], and to ground instrumentation such as HARPS [5], HATnet [6], WASP [7], KELT [8], OGLE [9], NGTS [10] and many others.…”