The European Space Agency (ESA) has approved plans to build the world’s first space telescope dedicated to studying the atmosphere of exoplanets.
Around 4,000 planets outside our solar system have been discovered since astronomer Michel Mayor and his colleagues confirmed that 51 Pegasi – detected by measuring the ‘wobbling’ motion of its parent star – was a large Jupiter-like planet in 1995.
Spectrographs aboard the telescope will study the light filtering from exoplanetary atmospheres as they pass across their stars, detecting the signatures of substances such as methane, carbon dioxide and water vapour, as well as exotic metallic compounds. The data will provide scientists with a more complete picture of the composition and temperature of exoplanets, giving clues as to how they formed and how they will evolve.
For a smaller number of exoplanets, Ariel will perform a deep survey of their cloud systems, and record seasonal and daily variations in atmosphere.
“We are the first generation capable of studying planets around other stars,” said Professor Giovanna Tinetti, Ariel’s principal investigator at UCL. “Ariel will seize this unique opportunity and reveal the nature and history of hundreds of diverse worlds in our galaxy. We can now embark on the next stage of our work to make this mission a reality.”
Ariel has been undergoing a review process throughout 2020. It is due for launch in 2029.
Significant funding for Ariel has come from the UK Space Agency, and UK research institutions (including University College London, Cardiff University, the University of Oxford, the Science and Technology Facilities Council’s RAL Space, and the UK Astronomy Technology Centre) will play roles in the project, including contributing vital hardware and software.
Science Minister Amanda Solloway commented: “Thanks to government funding, this ambitious, UK-led mission will mark the first large-scale study of planets outside the solar system and will enable our leading space scientists to answer critical questions on their formation and evolution.”
Paul Eccleston of STFC RAL Space added: “This represents the culmination of lots of preparatory work by our teams across the world over the last five years in order to demonstrate the feasibility and readiness of the payload. We can now go full-speed ahead to fully develop the design and start building prototypes of the instrumentation on the spacecraft.”