James Webb Space Telescope discovers rotating cradle of exomoon
Scientists have found evidence of the formation of a distant planet's lunar system
An illustrated disk forming a moon surrounds an alien planet.
NASA, ESA, CSA, STScI, Gabriele Cugno/University of Zurich, NCCR PlanetS, Sierra Grant/Carnegie Science, Joseph Olmstead/STScI, Leah Hustak/STScI
For the first time, scientists have directly detected molecules in a frisbee of gas and dust swirling around an alien gas giant planet. “I didn't think it was possible,” says astronomer Sierra Grant of Carnegie Science in Washington, DC. Normally such a weak signal would be invisible in the bright light of the star. Grant and her co-author Gabriele Cugno of the University of Zurich, who recently published the results. V Letters in an astrophysical journalI think the carbon-rich disk is a lunar nursery, and I'm already planning to observe a few more; researchers will eventually be able to detect gaps carved into such disks using nascent moons.
Grant and Cugno used the James Webb Space Telescope (JWST) to capture the infrared glow from the disk of gas and dust surrounding the Goliath world called CT Cha b. Noticing the light emitted by a planet (let alone the disk around it) is like seeing a firefly in a spotlight. It’s easier if the firefly is huge and located far from the light. CT Cha b weighs between 14 and 24 Jupiter masses and orbits its star about 17 times farther than Neptune from the Sun.
Previous observations had hinted that CT Cha b was consuming material from a yet-unseen disk, and Cugnot sought to separate that disk's infrared heat from the star's bright glow. Grant was skeptical that this would be possible, but Cugno wanted to test the JWST's capabilities. “It was almost a game,” he says.
About supporting science journalism
If you enjoyed this article, please consider supporting our award-winning journalism. subscription. By purchasing a subscription, you help ensure a future of influential stories about the discoveries and ideas shaping our world today.
Cugnot ultimately extracted from the data a “beautiful” light spectrum of the disk, in which Grant found clear chemical signatures of carbon-rich compounds such as hydrogen cyanide, acetylene, and even complex molecules such as six-carbon benzene rings – substances absent from the material orbiting directly around the star CT Cha b. The disk may be the formation zone of moons around the planet.
“This could give us clues about what kind of material is available to form exomoons,” says astrophysicist Danny Gasman of the Max Planck Institute for Astronomy in Germany, who was not involved in the study. However, she warns that while CT Cha b's size and vast distance from the star make it an excellent target, they also mean it may be more like a failed star than a typical gas giant.
Even in our solar system, the origin of satellites remains a mystery. Discs like CT Chab make it possible to understand not only the satellites of alien systems, but also the satellites of ours. “It’s very difficult to go back 4.5 billion years and imagine how they were created,” says Cugno. “Now we can actually see this process.”
It's time to stand up for science
If you liked this article, I would like to ask for your support. Scientific American has been a champion of science and industry for 180 years, and now may be the most critical moment in that two-century history.
I was Scientific American I have been a subscriber since I was 12, and it has helped shape my view of the world. science always educates and delights me, instills a sense of awe in front of our vast and beautiful universe. I hope it does the same for you.
If you subscribe to Scientific Americanyou help ensure our coverage focuses on meaningful research and discovery; that we have the resources to report on decisions that threaten laboratories across the US; and that we support both aspiring and working scientists at a time when the value of science itself too often goes unrecognized.
In return you receive important news, fascinating podcastsbrilliant infographics, newsletters you can't missvideos worth watching challenging gamesand the world's best scientific articles and reporting. You can even give someone a subscription.
There has never been a more important time for us to stand up and show why science matters. I hope you will support us in this mission.
