A planet that shouldn\u2019t exist is rewriting what scientists thought they knew about worlds beyond our solar system.<\/p>\n
Using NASA\u2019s James Webb Space Telescope, researchers have spotted an exoplanet with an atmosphere unlike anything previously observed, one so strange it blurs the line between planet and star.<\/p>\n
Officially named PSR J2322-2650b, the object is roughly the mass of Jupiter but bears little resemblance to a typical gas giant. <\/p>\n
It orbits a rapidly spinning neutron star, or pulsar, at an extremely close distance, enduring intense radiation and gravitational forces that stretch it into a lemon-like shape.<\/p>\n
What truly stunned scientists, however, was its atmosphere. Instead of familiar compounds such as water vapor or methane, Webb detected a mix dominated by helium and carbon, an exotic chemistry never before seen on a planet.<\/p>\n
\u201cThe planet orbits a star that\u2019s completely bizarre, the mass of the Sun, but the size of a city,\u201d said University of Chicago\u2019s Michael Zhang, the study\u2019s principal investigator.<\/p>\n
\u201cThis is a new type of planet atmosphere that nobody has ever seen before.\u201d<\/p>\n
\u201cThis was an absolute surprise,\u201d added team member Peter Gao of the Carnegie Earth and Planets Laboratory. \u201cI remember after we got the data down, our collective reaction was \u2018What the heck is this?’\u201d<\/p>\n
A planet without starlight<\/p>\n
PSR J2322-2650b circles its pulsar at a distance of just about one million miles, completing a full orbit every 7.8 hours. The host star emits mostly gamma rays and high-energy particles, which are invisible to Webb\u2019s infrared instruments.<\/p>\n
That unusual setup gave scientists a rare advantage. With the pulsar effectively invisible, the planet\u2019s faint glow could be studied in remarkable detail.<\/p>\n
\u201cThis system is unique because we are able to view the planet illuminated by its host star, but not see the host star at all,\u201d said Stanford University graduate student Maya Beleznay. \u201cSo we get a really pristine spectrum.\u201d<\/p>\n
The data revealed molecular carbon, specifically C\u2082 and C\u2083, floating through the planet\u2019s atmosphere, along with soot-like clouds. Deep inside, under extreme pressure, that carbon could even condense into diamonds.<\/p>\n
\u201cInstead of finding the normal molecules we expect to see on an exoplanet, like water, methane, and carbon dioxide, we saw molecular carbon, specifically C3 and C2,\u201d Zhang said.<\/p>\n
Formation theories fall apart<\/p>\n
The discovery raises a bigger question: how did such a planet form at all?<\/p>\n
\u201cIt\u2019s very hard to imagine how you get this extremely carbon<\/a>-enriched composition,\u201d Zhang said. \u201cIt seems to rule out every known formation mechanism.\u201d<\/p>\n The system resembles a rare \u201cblack widow\u201d pairing, where a pulsar slowly strips material from a smaller companion. But even that explanation falls short.<\/p>\n \u201cDid this thing form like a normal planet? No, because the composition is entirely different,\u201d Zhang said. <\/p>\n \u201cDid it form by stripping the outside of a star, like \u2018normal\u2019 black widow systems are formed? Probably not, because nuclear<\/a> physics does not make pure carbon.\u201d<\/p>\n Roger Romani of Stanford University suggests an unusual process may be at work. \u201cPure carbon crystals float to the top and get mixed into the helium,\u201d he said. \u201cBut then something has to happen to keep the oxygen and nitrogen away.\u201d<\/p>\n For now, the planet remains a cosmic puzzle.<\/p>\n