{"id":119,"date":"2025-12-13T15:03:03","date_gmt":"2025-12-13T14:03:03","guid":{"rendered":"https:\/\/www.harmoni-elt.eu\/harmoni\/?page_id=119"},"modified":"2025-12-13T15:03:20","modified_gmt":"2025-12-13T14:03:20","slug":"exoplanet-2","status":"publish","type":"page","link":"https:\/\/www.harmoni-elt.eu\/harmoni\/harmoni\/17-2\/exoplanet-2\/","title":{"rendered":"exoplanet"},"content":{"rendered":"\n
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Exoplanets: Directly characterising worlds beyond the Solar System<\/strong><\/h1>\n\n\n\n

Over the past two decades, thousands of exoplanets have been discovered, revealing an extraordinary diversity of planetary systems. However, understanding how these planets form, evolve, and acquire their atmospheric properties requires direct characterisation<\/strong>, beyond simple detection.<\/p>\n\n\n\n

HARMONI on the ELT will open a new era in exoplanet science<\/strong> by enabling spatially resolved, high-contrast spectroscopy of exoplanets, providing direct access to their atmospheres, compositions, and physical processes<\/strong>.<\/p>\n\n\n\n

\n\n\n\n

Direct imaging and spectroscopy of exoplanets<\/h2>\n\n\n\n

Direct imaging isolates the faint light of a planet from the overwhelming glare of its host star. When combined with integral-field spectroscopy, this technique provides simultaneous spatial and spectral information, allowing detailed atmospheric characterisation.<\/p>\n\n\n\n

With its extreme angular resolution and sensitivity, HARMONI will:<\/p>\n\n\n\n

    \n
  • Directly detect and spectroscopically characterise young, self-luminous exoplanets<\/strong><\/li>\n\n\n\n
  • Probe planetary atmospheres<\/strong> through molecular absorption features<\/li>\n\n\n\n
  • Measure effective temperatures, surface gravities, and compositions<\/strong><\/li>\n<\/ul>\n\n\n\n

    These observations are particularly powerful in the near-infrared, where planets emit strongly and key molecular species are accessible.<\/p>\n\n\n\n

    \n\n\n\n

    Atmospheric composition and structure<\/h2>\n\n\n\n

    HARMONI will enable detailed studies of exoplanet atmospheres, targeting molecular tracers such as:<\/p>\n\n\n\n

      \n
    • Water vapour<\/li>\n\n\n\n
    • Carbon monoxide and carbon dioxide<\/li>\n\n\n\n
    • Methane and other hydrocarbons<\/li>\n<\/ul>\n\n\n\n

      By measuring these species, astronomers can:<\/p>\n\n\n\n

        \n
      • Constrain atmospheric chemistry and metallicity<\/strong><\/li>\n\n\n\n
      • Investigate clouds and vertical structure<\/strong><\/li>\n\n\n\n
      • Test models of atmospheric circulation and heat transport<\/li>\n<\/ul>\n\n\n\n

        Medium to high spectral resolution allows separation of planetary signals from residual stellar light and enables precise measurements of atmospheric properties.<\/p>\n\n\n\n

        \n\n\n\n

        Planet formation and early evolution<\/h2>\n\n\n\n

        Young exoplanets provide a direct window into the planet formation process. Their luminosity, temperature, and atmospheric composition retain information about how and where they formed within their natal disks.<\/p>\n\n\n\n

        HARMONI will:<\/p>\n\n\n\n

          \n
        • Characterise planets at small angular separations<\/strong>, probing regions close to their host stars<\/li>\n\n\n\n
        • Distinguish between competing formation pathways<\/strong> (e.g. core accretion vs. gravitational instability)<\/li>\n\n\n\n
        • Measure chemical signatures linked to formation location and disk properties<\/li>\n<\/ul>\n\n\n\n

          These observations will place strong constraints on theoretical models of planet formation and migration.<\/p>\n\n\n\n

          \n\n\n\n

          Dynamics and planet\u2013star interactions<\/h2>\n\n\n\n

          Beyond atmospheric properties, HARMONI will probe the dynamical and physical interactions<\/strong> between planets and their environments.<\/p>\n\n\n\n

          This includes:<\/p>\n\n\n\n

            \n
          • Measuring orbital motion<\/strong> and dynamical masses for directly imaged planets<\/li>\n\n\n\n
          • Studying accretion signatures<\/strong> in forming or young planets<\/li>\n\n\n\n
          • Investigating the impact of stellar radiation and winds on planetary atmospheres<\/li>\n<\/ul>\n\n\n\n

            Such measurements are essential to connect observed planet populations to their long-term evolutionary paths.<\/p>\n\n\n\n

            \n\n\n\n

            Synergy with other facilities<\/h2>\n\n\n\n

            HARMONI\u2019s exoplanet science is highly complementary to other major facilities:<\/p>\n\n\n\n

              \n
            • High-contrast imagers<\/strong> that provide discovery and broadband characterisation<\/li>\n\n\n\n
            • JWST<\/strong>, which excels at unresolved spectroscopy of transiting planets<\/li>\n\n\n\n
            • Radial velocity and astrometric surveys<\/strong>, which constrain planet masses and orbits<\/li>\n<\/ul>\n\n\n\n

              Together, these approaches will build a comprehensive picture of exoplanet systems across a wide range of masses, ages, and environments.<\/p>\n\n\n\n

              \n\n\n\n

              A key step toward comparative planetology<\/h2>\n\n\n\n

              By delivering spatially resolved spectroscopy of exoplanets, HARMONI will:<\/p>\n\n\n\n

                \n
              • Enable comparative studies of planetary atmospheres<\/strong><\/li>\n\n\n\n
              • Link exoplanets to Solar System analogues<\/li>\n\n\n\n
              • Provide critical benchmarks for interpreting population-level trends<\/li>\n<\/ul>\n\n\n\n

                Exoplanet science is therefore a central pillar of HARMONI\u2019s scientific programme<\/strong>, connecting the study of nearby planetary systems to the broader quest to understand how planets form and evolve throughout the Galaxy.<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

                Exoplanets: Directly characterising worlds beyond the Solar System Over the past two decades, thousands of exoplanets have been discovered, revealing an extraordinary diversity of planetary systems. However, understanding how these planets form, evolve, and acquire their atmospheric properties requires direct characterisation, beyond simple detection. HARMONI on the ELT will open a new era in exoplanet […]<\/p>\n","protected":false},"author":3,"featured_media":0,"parent":17,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-119","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.harmoni-elt.eu\/harmoni\/wp-json\/wp\/v2\/pages\/119","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.harmoni-elt.eu\/harmoni\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.harmoni-elt.eu\/harmoni\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.harmoni-elt.eu\/harmoni\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.harmoni-elt.eu\/harmoni\/wp-json\/wp\/v2\/comments?post=119"}],"version-history":[{"count":2,"href":"https:\/\/www.harmoni-elt.eu\/harmoni\/wp-json\/wp\/v2\/pages\/119\/revisions"}],"predecessor-version":[{"id":121,"href":"https:\/\/www.harmoni-elt.eu\/harmoni\/wp-json\/wp\/v2\/pages\/119\/revisions\/121"}],"up":[{"embeddable":true,"href":"https:\/\/www.harmoni-elt.eu\/harmoni\/wp-json\/wp\/v2\/pages\/17"}],"wp:attachment":[{"href":"https:\/\/www.harmoni-elt.eu\/harmoni\/wp-json\/wp\/v2\/media?parent=119"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}