\n \u201cThis is one of the most bizarre planetary systems we know of,\u201d said Dr. Christopher O\u2019Connor, coauthor of a study published Wednesday in the journal Nature<\/a> that detailed the observations. O\u2019Connor is a postdoctoral fellow studying stellar and planetary astrophysics and dynamics at Northwestern University\u2019s Center for Interdisciplinary Exploration and Research in Astrophysics.\n <\/p>\n \n WD 1856 b completes one orbit around the dead star every 34 hours and is less than 2 million miles (3 million kilometers) from its host.\n <\/p>\n \n When a massive sunlike star exhausts the hydrogen fuel at its core, it puffs up to more than 100 times its size before collapsing into a dense white dwarf. Given the close proximity of WD 1856 b to its star \u2014 50 times closer than Earth is to our sun \u2014 astronomers were unsure how the planet survived its host\u2019s destruction.\n <\/p>\n \n In order to retrace WD 1856 b\u2019s unlikely journey of survival, O\u2019Connor and his colleagues used the James Webb Space Telescope to capture the latest glimpses of the planet and measure its atmosphere, mass and temperature. Almost every finding the team made was unexpected \u2014 and suggested that huge planets can survive the demise of their host stars in ways previously thought impossible.\n <\/p>\n \n The planet\u2019s tight orbit and the lopsided relative sizes of WD 1856 b and its host star motivated O\u2019Connor and his colleagues to investigate further.\n <\/p>\n \n \u201cFor a theoretical astrophysicist, finding a strange object located where it \u2018shouldn\u2019t be\u2019 feels a bit like an invitation from the universe to get creative in search of an explanation,\u201d O\u2019Connor wrote in an email.\n <\/p>\n \n But making observations with Webb was challenging. The team had limited chances to watch a transit, or the dip in starlight as a planet passes in front of its star. Dead white dwarfs are much dimmer than the planet-hosting stars normally observed with Webb, said study coauthor Victoria Boehm, a graduate student in the department of astronomy at Cornell University.\n <\/p>\n \n \u201cTo make things even harder, the planet\u2019s transit only lasts 8 minutes, so it\u2019s very much if you blink you miss it,\u201d Boehm said in a statement. \u201cCapturing enough light to see WD 1856 b\u2019s spectrum, while also doing so quickly enough to not miss the transit, is something only Webb can do.\u201d\n <\/p>\n \n But the spectrum, or data captured as light from the star passed through the planet\u2019s atmosphere, revealed previously unknown information about WD 1856 b.\n <\/p>\n \n The team determined that the planet is between four and 11 times the mass of Jupiter.\n <\/p>\n \n Infrared light emitted by WD 1856 b suggested that it has a temperature of about 260 degrees Fahrenheit (127 degrees Celsius) \u2014 about 240 degrees hotter than if it were solely being heated by the dead star.\n <\/p>\n \n \u201cThat was really what started us on the track of figuring out the planet\u2019s history from our data,\u201d O\u2019Connor said.\n <\/p>\n \n The team combined the new measurements with models of how giant planets like Jupiter and Saturn cool over time, which occurs at a predictable rate related to their mass.\n <\/p>\n \n The results showed that the planet originally orbited the star from a safer, much greater distance. But WD 1856 b heated up while migrating inward after the star died.\n <\/p>\n \n The researchers have two competing theories about how WD 1856 b ended up in its current, tight orbit.\n <\/p>\n \n The \u201cengulfment model\u201d suggests that the planet was actually swallowed by the host star as it ballooned in size before dying but managed to survive, O\u2019Connor said. The \u201cgravitational interaction model\u201d alternatively proposes that WD 1856 b avoided the star\u2019s death throes, but the gravitational influence of other objects in the system pushed it closer to the white dwarf, he added.\n <\/p>\n \n \u201cIn either situation, there is reason to think that the planet would get heated up on the inside as a byproduct of the violent migration process,\u201d O\u2019Connor said. \u201cIn the first scenario, we would expect the migration and heating to have occurred simultaneously with the death of the host star, or about six billion years ago. In the second scenario, it can happen billions of years later, due to the chaos of gravitational interactions.\u201d\n <\/p>\n \n The team\u2019s data seems to indicate that heating of the planet occurred about 1 billion years ago, which might rule out the chances of engulfment \u2014 as does the Webb spectrum, which picked up on hints of the planet\u2019s chemical composition.\n <\/p>\n \n \u201cWe saw the telltale signatures of small cloud particles and hydrocarbons, most likely methane, which is the first time we have seen an atmosphere on a planet transiting a dead star,\u201d Boehm said. \u201cWe recently observed four more transits of WD 1856 b with Webb to take a deeper look into its atmospheric chemistry and can\u2019t wait to see the results.\u201d\n <\/p>\n \n The abundance of methane adds another line of evidence that the planet didn\u2019t go through engulfment during the red giant phase since that would have diluted the gas\u2019 abundance as the planet accreted hydrogen from the star, said lead author Dr. Ryan MacDonald, lecturer in extrasolar planets at the University of St. Andrews in Scotland.\n <\/p>\n![\"The](\"https:\/\/www.newsbeep.com\/us\/wp-content\/uploads\/2026\/07\/stsci-01kv8kvjbyzhgagmdwzv6yqbtc.jpg\")
<\/p>\n