Ryan J. MacDonald<\/a>, a lecturer in extrasolar planets at the University of St. Andrews in Scotland.<\/p>\nAn impossible orbit<\/p>\n
When astronomers first discovered WD1856b, they were instantly puzzled. Located just 80 light-years from Earth, the gas giant is between four and 11 times more massive than Jupiter. While most stars are vastly larger than their planets, WD1856b orbits a relatively diminutive Earth-sized white dwarf. White dwarfs are dense stellar remnants left behind after a sun-like star exhausts its fuel and dies.<\/p>\n
\u201cThis is one of the most bizarre planetary systems we know of,\u201d O\u2019Connor said. \u201cThe planet\u2019s radius is about eight times larger than the white dwarf, and it orbits at an extremely close distance \u2014 completing a full revolution every 1.4 days.\u201d<\/p>\n
The close proximity is especially baffling because WD1856b shouldn\u2019t have survived its star\u2019s red giant phase. When sun-like stars run out of fuel, they balloon to more than 100 times their original size. Red giants often engulf nearby planets before collapsing into white dwarfs. When our sun dies, for example, it will swallow Mercury, Venus and possibly Earth.<\/p>\n
\u201cThe big question is how WD1856b ended up where it is today, and there are two theories,\u201d O\u2019Connor said. \u201cOne is that the planet was swallowed by its host star as it was dying and managed to survive on the other side. The other is that the migration took place due to the gravitational effect of other objects in the system. The white dwarf is part of a triple star system, and the outer companion stars could have influenced WD1856b\u2019s orbit.\u201d<\/p>\n
A lingering fever<\/p>\n
To investigate those possibilities, the research team used JWST to measure the planet\u2019s atmosphere, temperature and mass. Among their findings, they discovered the planet is significantly hotter than expected \u2014 about 400 Kelvin (127 degrees Celsius or 260 degrees Fahrenheit), roughly 240 degrees hotter than can be explained by the white dwarf\u2019s light alone.<\/p>\n
By combining the JWST measurements with models of how giant planets cool over time, the team reconstructed the planet\u2019s history. Because giant planets cool at predictable rates, O\u2019Connor could effectively trace the planet\u2019s temperature back in time. The team found the planet likely heated up as it moved toward its host \u2014 3 to 5.5 billion years after the star became a white dwarf. In this scenario, the planet remained at a safe distance during its star\u2019s destructive red giant phase and migrated to its present location much later.<\/p>\n
\u201cAs the planet moves inward, its interactions with the strong gravity of the white dwarf caused it to warm up considerably,\u201d O\u2019Connor said. \u201cIt has been cooling ever since.\u201d<\/p>\n
\u2018Stellar death is not the end\u2019<\/p>\n
This planetary system could offer a preview of our own solar system\u2019s distant fate. Rather than ending when the sun dies, our system may continue evolving for billions of years afterward.<\/p>\n
“We\u2019re used to looking back in time when we use telescopes, but this is the first time we have been able to look forward to what might happen to the outer planets around the remnant of a sun-like star,\u201d MacDonald said. \u201cIt’s like using a time machine to peer into the distant future of our solar system.”<\/p>\n
The observations also revealed methane and clouds in the planet\u2019s atmosphere. The study marks the first time scientists have characterized the atmosphere of a planet orbiting a dead star.<\/p>\n
\u201cThis is just the beginning of our exploration of planets orbiting dead stars with JWST, and the search for further planets orbiting white dwarfs is ongoing,\u201d MacDonald said. \u201cOur results show that stellar death is not the end \u2014 some planets experience a vibrant and lively future after the death of their star.\u201d<\/p>\n
The study, \u201cAerosols and hydrocarbons in the atmosphere of a white dwarf planet,\u201d was supported by NASA and the National Science Foundation.<\/p>\n","protected":false},"excerpt":{"rendered":"EMBARGOED UNTIL 11 A.M. EDT (U.S) ON WEDNESDAY, JULY 1, 2026 \u00a0 \u00a0 \u00a0Gas giant orbits its dead…\n","protected":false},"author":2,"featured_media":16844,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[61,60,82],"class_list":["post-527840","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-ie","tag-ireland","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/527840","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/comments?post=527840"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/527840\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media\/16844"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media?parent=527840"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/categories?post=527840"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/tags?post=527840"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}