Title of programme: Axis 1 - Solidifying Planet-Star Composition Links by Studying Why the Internal Structures of Planets Across the Galaxy Vary (YGAL)
Abstract: Terrestrial planets form through the accretion of building blocks from dust grains to proto-planets. Heavier components sink and form metallic cores, whilst pebbles from beyond snow lines deliver volatiles influencing atmospheres or water on Earth-like planets. Understanding the composition of planetary ingredients is vital. Planetary refractory elemental abundances mirror stellar values; the Earth is a devolatised piece of the Sun. If this is universal we would expect a diversity in internal structures and atmospheres of planets orbiting metal-diverse stars. This is currently not well investigated, however in recent years tantalising evidence has emerged for metallicity-driven trends in the physical characteristics of super-Earth and sub-Neptune exoplanets. These first pieces of evidence might be pointing towards chemically-diverse formation scenarios impacting the internal structures of planets, however this is currently unclear as there are very few well-characterised small planets around metal-poor stars. Therefore, this program will refine the radii of a handful of key planets around Galactic thick-disk, metal-poor host stars to an unprecedented level in order to solve the current mysteries that we are just starting to unravel.
Temporal Coverage
2024-02-17T09:44:00Z / 2024-02-17T22:10:00Z
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.
