Title of programme: Axis 2 - Beyond Geometrical Albedo: A deeper understanding of the reflective behavior of exoplanet atmospheres (BENGAL)
Abstract: Our knowledge of the reflective properties of exoplanet atmospheres is extremely limited outside of the Solar System planets. The geometric and Bond albedo measurements constitute the majority of the subjects observational constraints. Reflected light phase curves hold the key to gaining a better understanding of the fundamental scattering properties: single scattering albedo and asymmetry, as well as determining the degree of inhomogeneity in the spatial distribution of clouds, hazes, and aerosols. However, due to observational biases, the vast majority of existing datasets that show a clear phase curve signal in the visible are aimed at hot gas giants. As a result, they are plagued by the degeneracy between reflected and thermal light. Only Kepler-7 b was cool enough and Kepler sensitive enough to deliver a high precision phase curve that is dominated by reflected light. Kepler-7 b is thus the only exoplanet for which we have direct measurements of cloud distribution inhomogeneity and fundamental scattering properties. With this program, we will leverage CHEOPS’ photometric precision, bandpass and pointing flexibility to perform repeated phase curves observations of a few key targets. These canonical datasets will provide precise reflected light phase curves and will offer long-awaited counterparts to Kepler-7 b. We will investigate atmospheric inhomogeneity and measure fundamental scattering properties. We will begin to explore the diversity of exoplanet atmospheres by focusing on planets with different properties than Kepler-7 b.
Temporal Coverage
2023-09-06T20:20:00Z / 2023-09-10T00:54:00Z
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.
