Sensitivity and performance of the Ariel Space Telescope

Ariel will spectroscopically characterise the atmospheres of a large and diverse sample of hundreds of exoplanets. Targets will be selected to cover a wide range of masses, densities, equilibrium temperatures, and host stellar types, enabling the study of the physical mechanisms driving the observed diversity in the known exoplanet population. Transmission, emission, and phase-curve spectroscopy of transiting exoplanet atmospheres require the detection of very small (<100 ppm) modulations in the signal of bright host stars. The Ariel mission design incorporates three photometers and three spectrometers simultaneously covering the 0.5–7.8 μm band, and implements solutions optimised to achieve the required sensitivity while controlling systematics of both astrophysical and instrumental origin. This contribution reviews the predicted end-to-end performance that will enable Ariel to reach its sensitivity goals and maintain stringent control over systematic effects.