{"id":9864,"date":"2026-04-06T10:08:30","date_gmt":"2026-04-06T14:08:30","guid":{"rendered":"https:\/\/spaceandplanetarynewswire.com\/?p=9864"},"modified":"2026-04-06T10:08:30","modified_gmt":"2026-04-06T14:08:30","slug":"how-did-this-get-made-giant-planet-orbits-small-star","status":"publish","type":"post","link":"https:\/\/spaceandplanetarynewswire.com\/?p=9864","title":{"rendered":"How Did This Get Made? Giant Planet Orbits Small Star"},"content":{"rendered":"
An artist\u2019s conception of the gas giant planet TOI-5205 b orbiting a small, cool red dwarf star. Image courtesy Katherine Cain, Carnegie Science.<\/figcaption><\/figure>\n

Observations of the highly unusual\u2014sometimes called \u201cforbidden\u201d\u2014exoplanet TOI-5205 b taken by JWST suggest the giant planet\u2019s atmosphere has fewer heavier elements than its host star. These findings have implications for our understanding of the giant planet formation process that occurs early in a star\u2019s lifespan.<\/p>\n

Published this week by\u00a0The Astronomical Journal<\/em>,<\/a>\u00a0these findings represent the collaborative work of an international team of astronomers led by NASA Goddard Space Flight Center\u2019s Caleb Ca\u00f1as and including Carnegie Science\u2019s Shubham Kanodia.<\/p>\n

TOI 5205 b is a Jupiter-sized planet orbiting a star that is itself about four times the size of Jupiter and about 40 percent the mass of the Sun. When it passes in front of its host star\u2014a phenomenon astronomers call a \u201ctransit\u201d\u2014the planet blocks about six percent of its light. \u00a0By observing this transit with telescope instruments called spectrographs that split the light into its constituent colors, astronomers can try to decipher the planet\u2019s atmospheric makeup and learn more about its history and relationship with its host star.<\/p>\n

Planets are born from the rotating disk of gas and dust that surrounds a star in its youth. While it is commonly accepted that giant planets form in these cloudy disks that result from the birth of the host star, the existence of massive planets like TOI-5205b orbiting cool stars at close distances raises many questions about this process.<\/p>\n

To shed more light on this, Kanodia, Ca\u00f1as and Jessica Libby-Roberts of the University of Tampa are leading the largest JWST Cycle 2 exoplanet program,\u00a0Red Dwarfs and the Seven Giants<\/em>, which was designed to study unlikely worlds like TOI-5205 b\u2014sometimes called GEMS (for giant exoplanets around M dwarf stars).<\/p>\n

Back in 2023, Kanodia led the effort that confirmed TOI-5205 b\u2019s existence, following up on information from NASA\u2019s Transiting Exoplanet Survey Satellite (TESS), which first identified it as a planetary candidate. Now, he\u2019s co-leading the team that made the first observations of its atmospheric composition.<\/p>\n

Their observations of three transits of TOI5205-b revealed something that the astronomers couldn\u2019t easily explain. They were surprised to see that the planet\u2019s atmosphere has a lower concentration of heavy elements\u2014relative to hydrogen\u2014than a gas giant planet in our own Solar System like Jupiter. It even has a lower metallicity than its own host star. This makes it stand out among all the giant planets that have been studied to date.<\/p>\n

Additionally, although less shocking, the transits revealed methane (CH\u2084) and hydrogen sulfide (H\u2082S) in TOI-5205-b\u2019s atmosphere.<\/p>\n

To contextualize their findings, team members Simon Muller and Ravit Helled at University of Zurich deployed sophisticated models of planetary interiors to predict that the entirety of TOI5205-b\u2019s composition is about 100 times more metal rich than its atmosphere, as measured by the transits.<\/p>\n

\u201cWe observed much lower metallicity than our models predicted for the planet\u2019s bulk composition, which is calculated from measurements of a planet\u2019s mass and radius. This suggests that its heavy elements migrated inward during formation and now its interior and atmosphere are not mixing,\u201d Kanodia explained. \u201cIn summary, these results suggest a very carbon-rich, oxygen-poor planetary atmosphere.\u201d<\/p>\n

The research is part of the GEMS Survey, a program dedicated to studying transiting giant planets around M-dwarf stars to understand their formation, structure, and atmospheres.<\/p>\n","protected":false},"excerpt":{"rendered":"

Observations of the highly unusual\u2014sometimes called \u201cforbidden\u201d\u2014exoplanet TOI-5205 b taken by JWST suggest the giant planet\u2019s atmosphere has fewer heavier elements than its host star. These findings have implications for our understanding of the giant planet formation process that occurs early in a star\u2019s lifespan. Published this week by\u00a0The Astronomical Journal,\u00a0these findings represent the collaborative…<\/p>\n","protected":false},"author":71,"featured_media":9865,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ngg_post_thumbnail":0,"fifu_image_url":"https:\/\/carnegiescience.edu\/sites\/default\/files\/2026-04\/TOI%205205b%E2%80%94transiting%E2%80%94Shubham%20%281%29.jpg","fifu_image_alt":"","footnotes":""},"categories":[216],"tags":[],"class_list":["post-9864","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-discovery"],"_links":{"self":[{"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=\/wp\/v2\/posts\/9864","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=\/wp\/v2\/users\/71"}],"replies":[{"embeddable":true,"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=9864"}],"version-history":[{"count":1,"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=\/wp\/v2\/posts\/9864\/revisions"}],"predecessor-version":[{"id":9866,"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=\/wp\/v2\/posts\/9864\/revisions\/9866"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=\/wp\/v2\/media\/9865"}],"wp:attachment":[{"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=9864"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=9864"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=9864"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}