![\"\"](\"https:\/\/www.europesays.com\/uk\/wp-content\/uploads\/2026\/06\/Illustration-planets-TOI-791b-and-TOI-791c-with-host-star-TOI-791-Credit-NASA-and-Daniel-Rutter.jpg\")
Illustration planets TOI-791b and TOI-791c with host star TOI-791 Credit: NASA\/Daniel Rutter<\/p>\n Illustration planets TOI-791b and TOI-791c with host star TOI-791 Credit: NASA\/Daniel Rutter<\/p>\n
Two \u2018super-puff\u2019 planets lighter than candy candy have been discovered by scientists\u2014and they\u2019re bigger than Jupiter.<\/p>\n
They are among the lowest-density giant planets ever detected, according to a new study.<\/p>\n
The two planets orbit a dwarf star located around 1,110 light years from Earth in the southern constellation of Volans.<\/p>\n
Although both planets\u2014named TOI-791b and TOI-791c\u2014are around the size of Jupiter, researchers say they are \u201cextraordinarily\u201d diffuse.<\/p>\n
Jupiter\u2019s density is 1.33 grams per cubic centimeter, while TOI-791b has a density of just 0.038 grams per cubic cm, and TOI-791c\u2019s density is just 0.047\u2014that\u2019s 28 to 35 times lighter.<\/p>\n
The new planets\u2019 densities are even lower than cotton candy, which typically has a density of about 0.05 grams per cubic centimeter. In contrast, Earth\u2019s density is 5.5 grams per cubic centimeter, according to the study published in the journal<\/a> Monthly Notices of the Royal Astronomical Society, led by University of Oxford scientists working with researchers from the University of Birmingham and the Universit\u00e9 C\u00f4te d\u2019Azur in France.<\/p>\n The planets are \u201csiblings\u201d believed to have formed together from the same disc of gas and dust surrounding their young star.<\/p>\n They are also locked in a rare gravitational relationship known as a 5:3 mean-motion resonance, meaning that for every five orbits completed by the inner planet, the outer planet completes almost exactly three.<\/p>\n The research team says that gravitational interaction causes the planets to repeatedly \u201ctug\u201d on one another, producing measurable shifts in the timing of their transits across the host star.<\/p>\n \u201cOnly a handful of these super-puffy planets are known, and it is even rarer to find two in the same system,\u201d said lead author<\/a> Dr. George Dransfield, from Oxford.<\/p>\n \u201cTheir extremely low densities make them fascinating targets for understanding how planetary systems form and evolve.\u201d<\/p>\n They were found by citizen scientists \u2013 and an Antarctica telescope was critical<\/p>\n They were first identified as possible planets by citizen-science volunteers participating in the Planet Hunters TESS project, which searches NASA data for possible new worlds.<\/p>\n MORE FASCINATING PLANETS:<\/strong> Scientists then measured the planets\u2019 densities by combining observations of their sizes and masses using telescopes located around the world, including Antarctica (where the ASTEP is located\u2014Antarctic Search for Transiting ExoPlanets).<\/p>\n The Antarctic winter provided a unique advantage for one of their telescopes: months of continuous darkness enabled astronomers to capture the planets\u2019 exceptionally long transits, each lasting more than 11 hours, in a single uninterrupted observation\u2014the longest continuous planetary transits ever observed in their entirety from the ground.<\/p>\n Transits are crucial for the research because when a planet passes in front of its host star the view slightly dims the star\u2019s light, and the amount of dimming reveals the planet\u2019s size.<\/p>\n The researchers detected subtle variations in the timing of the transits, caused by the two planets gravitationally tugging on one another as they orbit the star. By analyzing the timing shifts, the team was able to estimate the planets\u2019 masses and calculate their remarkably low densities.<\/p>\n \u201cBringing together observations from Antarctica, space telescopes, and observatories across several continents was essential to revealing the true nature of these extraordinary planets,\u201d said co-author Professor Tristan Guillot, from the Universit\u00e9 C\u00f4te d\u2019Azur<\/p>\n Astronomers are still debating how super-puff planets form.<\/p>\n The researchers intend to carry out further investigations to understand more about how the puff-planets formed, and to rule out some of the explanations.<\/p>\n INCREDIBLE SPACE PHOTOS:<\/strong> \u201cWe propose to carry out space-based observations using the James Webb Space Telescope to assess if the puffy atmosphere contains carbon-, nitrogen-, and oxygen-bearing species, revealing new insight into how these unusual planets formed,\u201d explained study co-author Professor Amaury Triaud, from the University of Birmingham.<\/p>\n DO A SOLID FOR ASTRONOMY-LOVERS By Sharing the Awe on Social Media\u2026<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"Illustration planets TOI-791b and TOI-791c with host star TOI-791 Credit: NASA\/Daniel Rutter Two \u2018super-puff\u2019 planets lighter than candy…\n","protected":false},"author":2,"featured_media":1059238,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_share_on_mastodon":"0"},"categories":[8],"tags":[901,30206,46355,70,413,36189,16,15],"class_list":["post-1059237","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-astronomy","tag-discovery","tag-odd","tag-science","tag-space","tag-stargazing","tag-uk","tag-united-kingdom"],"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@uk\/116838120344786544","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts\/1059237","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/comments?post=1059237"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts\/1059237\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/media\/1059238"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/media?parent=1059237"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/categories?post=1059237"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/tags?post=1059237"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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