No thick carbon dioxide atmosphere on the rocky exoplanet TRAPPIST-1 c

Abstract Seven rocky planets orbit the nearby dwarf star TRAPPIST-1, providing a unique opportunity to search for atmospheres on small planets outside the Solar System 1 . Thanks to the recent launch of the James Webb Space Telescope (JWST), possible atmospheric constituents such as carbon dioxide (CO 2 ) are now detectable 2,3 . Recent JWST observations of the innermost planet TRAPPIST-1 b showed that it is most probably a bare rock without any CO 2 in its atmosphere 4 . Here we report the detection of thermal emission from the dayside of TRAPPIST-1 c with the Mid-Infrared Instrument (MIRI) on JWST at 15 µm. We measure a planet-to-star flux ratio of f p / f ⁎ = 421 ± 94 parts per million (ppm), which…

• NA
  National Aeronautics and Space Administration

  Awards: 5-03127, NAS 5-03127, 80NSSC18K0829
• ST
  Space Telescope Science Institute

  Awards: 5-03127, NAS 5-03127
• FD
  Fonds De La Recherche Scientifique - FNRS
• BF
  Belgian Federal Science Policy Office
• NS
  Nuclear Safety and Security Commission