ARIEL

ARIEL [Airbus Defence and Space]

ARIEL (Atmospheric Remote-sensing Infrared Exoplanet Large-survey) is an ESA mission with the objective to perform a chemical census of a large (of order 1000) well selected diverse sample of primarily warm and hot exoplanets orbiting relatively nearby host stars with a range of spectral types from A to M.

The key science questions ARIEL will address are:

• What are the physical processes shaping planetary atmospheres?
• What are exoplanets made of?
• How do planets and planetary systems form and evolve?

The target selection will be made before launch based on ESA science team and community inputs, and can be updated throughout the mission. The mission will deliver a homogeneous catalogue of planetary spectra, yielding refined molecular abundances, chemical gradients and atmospheric structure; diurnal and seasonal variations; presence of clouds and measurement of albedo.

Ariel will perform observations in three photometric bands (0.5-0.6 micron, 0.6-0.8 micron, and 0.8-1.1 micron) and three spectroscopic bands (1.1-1.95 micron (R>15), 1.95-3.9 micron (R>100), and 3.9-7.8 micron (R>30)) simultaneously covering the 0.5-7.8 micron spectral range, with an off-axis Cassegrain telescope having a 1.1 × 0.7 m primary providing a collecting area of 0.61 m².