2239362

Target RA (J2000): 36.868244 and deg Target Dec (J2000): -27.63518 and deg Gaia GMag: 8.9 Programme ID: CH_PR230021 PI of observing programme: Dragomir Title of programme: Exploring the Diversity of Small Planet Compositions Abstract: The sizes and masses of planets provide a powerful constraint on their composition. But until recently the exoplanet community had access to large samples of just radii for small planets. TESS is enabling us to finally also measure the masses of an ensemble of small planets. Complementarily we propose to use CHEOPS to measure precise radii for seven small TESS planets in order to constrain their interior composition and explore the period-radius valley. The proposed observations will also serve to constrain the orbital eccentricity of these planets provide an anchor point at visible wavelengths for infrared transmission spectroscopy observations. For one planet it may also significantly refine the ephemeris since it is not yet known whether TESS will re-observe it. [truncated! Please see actual data for full text]