Ariel space mission

Project homepage
Official Arieli mission homepage

Ariel is a European Space Agency space telescope, designed to measure the atmospheric composition of exoplanet atmospheres. Exoplanets are planets around stars other than the sun and, as of 2020, around 5000 such planets are known. The next big challenge in the field is the systematic and detailed study of exoplanet atmospheres.

Ariel was selected as the fourth medium-class mission in ESA’s Cosmic Vision programme. During its 4-year mission, Ariel will study what exoplanets are made of, how they formed, and how they evolve. It will do this by surveying a diverse sample of about 1000 extrasolar planets, simultaneously in visible and infrared wavelengths. The spectroscopic analysis of starlight that has passed through a planet’s atmosphere will reveal its chemical composition, presence of clouds or hazes, and thermal structure. This is the first telescope entirely dedicated to measuring the chemical composition and thermal structures of exoplanet atmospheres, enabling planetary and atmospheric science far beyond the boundaries of the Solar System.

Some of the keys to Ariel’s success are the choice of planets to observe and the determination an accurate measurement time. Scientists in the Stellar Physics group at UT’s Tartu Observatory are participating in this work through the spectroscopic and photometric characterisation of exoplanetary systems. Our team is determining the fundamental parameters and chemical element content of exoplanet host stars, which enables the choice and scientific interpretation of Ariel observations. We are also measuring exoplanet transit lightcurves to improve the precision of their orbital parameters, which is essential for the scheduling of Ariel observations.

Ariel is expected to launch to space in 2029.