NASA has announced that it will contribute instruments to European space missions that will explore the atmosphere of planets or extrasolar planets orbiting stars outside our Sun for the first time. This instrument will help ARIEL or the European Agency Agency (ESA) Remote-sensing Infrared Exoplanet Large-surveying Atmosphere.
The NASA instrument has been called CASE or Contribution to ARIEL Exoplanet Spectroscopy and will be managed by NASA's Jet Propulsion Laboratory in Pasadena, California, with JPL astrophysicist Mark Swain as lead researcher. The ARIEL spacecraft with CASE on board is expected to be launched in 2028.
So far, scientists have found more than 4,000 exoplanets in the Milky Way galaxy with the help of NASA's Kepler space telescope and TESS which is currently active (Transiting Exoplanet Survey Satellite). The space agency said that ARIEL would carry out planet hunting through transit one step further.
NASA says that ARIEL will be able to see the chemical fingerprints, or "spectrum," of a planet's atmosphere in the light of its star. "Spacecraft will observe starlight flowing through the atmosphere of the planets as they pass in front of their stars, as well as the light emitted by the atmosphere of the planets just before and after they disappear behind their stars," NASA explained .
The space agency said that this fingerprint would enable scientists to study the composition, temperature, and chemical processes in the planet's atmosphere observed by ARIEL.
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The chemical fingerprints of the exoplanet's atmosphere are very dim, so identifying them is a big challenge for astronomers. A telescope is needed to stare at individual stars for a long time and ARIEL will be the first spacecraft fully devoted to the task. It will observe hundreds of extrasolar planetary atmospheres, looking to identify their contents, temperatures and chemical processes.
With the addition of CASE, ARIEL will be able to observe clouds and fog as well which will provide a more comprehensive picture of the exoplanet's atmosphere. CASE will also allow measuring the albedo of each planet, the amount of light reflected by the planet.