In a groundbreaking discovery, NASA’s James Webb Space Telescope has directly imaged two massive infant planets orbiting a young sun-like star, offering rare insight into the early stages of planetary formation.
The two gas giants, both larger than Jupiter, were observed in a distant planetary system located about 310 light-years away in the constellation Musca. The host star, named YSES-1, is only 16 million years old—an astronomical newborn compared to our 4.5-billion-year-old Sun.
What astonished astronomers was that the two planets, born from the same protoplanetary disk, appear to be at notably different stages of development. The innermost planet, with a mass about 14 times that of Jupiter, is encircled by a dusty disk and orbits its star at a distance 160 times that of Earth’s orbit from the Sun. Webb detected water and carbon monoxide in its atmosphere, suggesting it may still be forming, or possibly reshaping after a collision or moon formation event.
In contrast, the outer planet, about six times the mass of Jupiter and twice as far out as its sibling, has no surrounding disk. Instead, it features a thick atmosphere rich in silicate clouds and traces of methane, water, carbon monoxide, and carbon dioxide, distinctly different from any planet in our solar system.
“This is a fascinating system,” said lead researcher Kielan Hoch of the Space Telescope Science Institute in Baltimore. “Theoretically, the planets should be forming around the same time, but what we see suggests otherwise.”
The unusual characteristics raise big questions about planet formation. Why do the planets differ so much in composition and structure? And why are they orbiting so far from their star, beyond the typical regions of planet formation?
“These findings challenge long-standing assumptions about how planets form and evolve, including in our own solar system,” Hoch added. “Webb is reshaping what we thought we knew.”
Since becoming operational in 2022, the Webb Telescope has revolutionized the study of exoplanets with its advanced infrared imaging, uncovering atmospheric chemistry and planetary behaviors never observed before. This latest discovery, published this week in Nature, adds to Webb’s growing legacy of revealing the universe’s most elusive secrets.
Written By Rodney Mbua
