{"id":666378,"date":"2026-05-26T17:02:16","date_gmt":"2026-05-26T17:02:16","guid":{"rendered":"https:\/\/www.newsbeep.com\/us\/666378\/"},"modified":"2026-05-26T17:02:16","modified_gmt":"2026-05-26T17:02:16","slug":"super-jupiters-expose-a-long-standing-space-mystery","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/us\/666378\/","title":{"rendered":"Super Jupiters Expose a Long Standing Space Mystery"},"content":{"rendered":"

\"Gas<\/a>One way gas giants form is through core accretion, where solid cores gradually grow in a disk by pulling in rocky and icy pebbles until they become massive enough to attract the gas that surrounds young stars. Credit: Jean-Baptiste Ruffio<\/p>\n

Astronomers using the James Webb Space Telescope have uncovered surprising evidence about how enormous \u201csuper Jupiter\u201d planets are born.<\/p>\n

The discovery blurs the line between massive planets and brown dwarfs, the objects often called failed stars.<\/p>\n

Giant Gas Planets Push the Limits of Planet Formation<\/p>\n

Gas giants are enormous planets made mostly of hydrogen and helium. Even though they likely contain dense cores, they do not have solid surfaces like Earth. In our solar system, Jupiter and Saturn are the best-known examples, but astronomers have discovered many giant exoplanets beyond our solar system, including some that are far larger than Jupiter. The biggest of these worlds begin to overlap with brown dwarfs \u2014 objects often described as \u201cfailed stars\u201d because they do not sustain hydrogen fusion.<\/p>\n

Scientists have long debated how these giant planets form. One theory, known as core accretion, suggests that rocky and icy material slowly gathers inside a disk surrounding a young star. Over time, this growing core becomes massive enough to pull in huge amounts of gas, creating a giant planet like Jupiter or Saturn. Another possibility is gravitational instability, where part of the gas disk rapidly collapses and forms a massive object in a process more similar to star formation.<\/p>\n

Researchers led by the University of California San Diego used observations from the James Webb Space Telescope (JWST) to investigate this mystery in the HR 8799 star system. Their findings, published in Nature Astronomy, point toward an unexpected answer.<\/p>\n

HR 8799 and Its Massive Exoplanets<\/p>\n

The HR 8799 system sits about 133 light-years away in the constellation Pegasus. Its planets are enormous, ranging from five to ten times Jupiter\u2019s mass. They orbit very far from their host star at distances between 15 and 70 astronomical units. Even the innermost planet is 15 times farther from its star than Earth is from the Sun. The planet masses range from 5\u221210 MJup, meaning the smallest world in the system is still five times more massive than Jupiter.<\/p>\n

Astronomers often describe HR 8799 as an oversized version of our solar system because it contains four outer giant planets similar in arrangement to Jupiter through Neptune. However, the planets\u2019 extreme masses and wide orbits created a problem for older theories of planet formation. Traditional core accretion models suggested planets this massive would not have enough time to form before the young star cleared away the surrounding disk of gas and dust.<\/p>\n

Did You Know?<\/p>\n

What\u2019s the difference between a gas giant, brown dwarf and star? It comes down to a few factors:<\/p>\n

Mass: Stars are the most massive (80 MJup+), then brown dwarfs (13-80 MJup), then gas giants (below 13 MJup) [MJup = 1 Jupiter mass]<\/p>\n

Processing power: Stars fuse hydrogen, which produces intense heat and light; brown dwarfs can fuse deuterium, which produces much less intense heat and light; gas giants have no nuclear fusion<\/p>\n

Formation: Stars and brown dwarfs form through the direct collapse of an interstellar cloud of gas and dust, while planets form in the disk of material surrounding new-born stars. Planets first accrete tiny pebbles to form a core, which is then followed by runaway accretion of the surrounding gas to form gas giants.<\/p>\n

JWST Reveals Clues in Alien Atmospheres<\/p>\n

To study these distant worlds, astronomers used spectroscopy \u2014 the analysis of light to determine the composition and properties of objects in space. Before JWST, scientists mainly relied on ground-based telescopes to measure molecules such as water and carbon monoxide in exoplanet atmospheres. But researchers eventually realized that molecules containing carbon and oxygen are not the best indicators of how planets form because their origins are difficult to trace.<\/p>\n

Instead, the team focused on more stable materials known as refractory elements. Sulfur is one of these elements and exists only in solid material within the protoplanetary disk where planets take shape. Finding sulfur in a gas giant atmosphere strongly suggests the planet formed through core accretion.<\/p>\n

\u201cWith its unprecedented sensitivity, JWST is enabling the most detailed study of the atmospheres of these planets, giving us clues to their formation pathways. With the detection of sulfur, we are able to infer that the HR 8799 planets likely formed in a similar way to Jupiter despite being five to ten times more massive, which was unexpected,\u201d stated Jean-Baptiste Ruffio, a research scientist at UC San Diego and first co-author of the paper.<\/p>\n

HR 8799 is also relatively young at about 30 million years old (for reference, our solar system is about 4.6 billion years old). Young planets remain hotter and brighter than older ones, making them easier to study with spectroscopy.<\/p>\n

JWST\u2019s spectrograph provides extremely high-resolution observations from space, avoiding interference from Earth\u2019s atmosphere. For the first time, astronomers identified detailed signatures from several rare molecules in the atmospheres of the system\u2019s three inner gas giants that had previously remained hidden.<\/p>\n

Detecting Sulfur and Hydrogen Sulfide<\/p>\n

The discovery required overcoming major technical challenges. The planets are about 10,000 times dimmer than their host star, and JWST\u2019s spectrograph was not originally designed for this kind of observation. Ruffio developed new data analysis methods to separate the faint planetary signals from the overwhelming starlight. Jerry Xuan, a 51 Pegasi b Fellow at UCLA, built advanced atmospheric models to compare against the JWST observations and determine whether sulfur was present.<\/p>\n

\u201cThe quality of the JWST data is truly revolutionary, and existing atmospheric model grids were simply not adequate. To fully capture what the data were telling us, I iteratively refined the chemistry and physics in the models,\u201d he said. \u201cIn the end, we detected several molecules in these planets \u2014 some for the first time, including hydrogen sulfide.\u201d<\/p>\n

The clearest evidence of sulfur appeared on the planet HR 8799 c, although researchers suspect sulfur exists on all three inner planets. The team also discovered that these planets contain more heavy elements, including carbon and oxygen, than their parent star. That enrichment provides additional support for the idea that the objects formed as planets.<\/p>\n

Rethinking the Limits of Planet Size<\/p>\n

\u201cThere are many models of planet formation to consider. I think this shows that older core accretion models are outdated,\u201d stated UC San Diego Professor of Astronomy and Astrophysics Quinn Konopacky, another of the paper\u2019s co-authors. \u201cAnd of the newer models, we are looking at ones where gas giants can form solid cores really far away from their star.\u201d<\/p>\n

According to Ruffio, HR 8799 remains unusual because it is currently the only directly imaged system known to contain four massive gas giants. However, astronomers have identified other systems with even larger companions whose origins are still uncertain.<\/p>\n

\u201cI think the question is, how big can a planet be?\u201d he stated. \u201cCan a planet be 15, 20, 30 times the mass of Jupiter and still have formed like a planet? Where is the transition between planet formation and brown dwarf formation?\u201d<\/p>\n

Scientists are continuing to search for answers by studying more planetary systems across the galaxy.<\/p>\n

Reference: \u201cJupiter-like uniform metal enrichment in a system of multiple giant exoplanets\u201d by Jean-Baptiste Ruffio, Jerry W. Xuan, Yayaati Chachan, Aurora Kesseli, Eve J. Lee, Charles Beichman, Klaus Hodapp, William O. Balmer, Quinn Konopacky, Marshall D. Perrin, Dimitri Mawet, Heather A. Knutson, Geoffrey Bryden, Thomas P. Greene, Doug Johnstone, Jarron Leisenring, Michael Meyer and Marie Ygouf, 9 February 2026,\u00a0Nature Astronomy.
DOI: 10.1038\/s41550-026-02783-z<\/a><\/p>\n

Partial list of authors: Jean-Baptiste Ruffio, Eve J. Lee and Quinn Konopacky (all UC San Diego); Jerry W. Xuan (California Institute of Technology and UCLA); Dimitri Mawet, Aurora Kesseli, Charles Beichman, Geoffrey Bryden and Thomas P. Greene (all California Institute of Technology); and Yayaati Chachan (UC Santa Cruz). Full list of authors appears in the paper.<\/p>\n

This work was supported, in part, by the National Aeronautics and Space Administration (80NSSC25K7300 and FINESST Fellowship award 80NSSC23K1434). Any opinions, findings, and conclusions or recommendations expressed in this work are those of the author(s) and do not necessarily reflect the views of the National Aeronautics and Space Administration.<\/p>\n

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Follow us on Google<\/a> and Google News<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"One way gas giants form is through core accretion, where solid cores gradually grow in a disk by…\n","protected":false},"author":2,"featured_media":666379,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[48],"tags":[6626,22246,6625,79,193,56519],"class_list":["post-666378","post","type-post","status-publish","format-standard","has-post-thumbnail","category-space","tag-astronomy","tag-exoplanet","tag-planets","tag-science","tag-space","tag-ucsd"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/666378","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/comments?post=666378"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/666378\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media\/666379"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media?parent=666378"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/categories?post=666378"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/tags?post=666378"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}