Astronomers utilizing the NASA/ESA/CSA James Webb Space Telescope have discovered a silicate cloud in the atmosphere of the exoplanet YSES-1C and a disk in the evasion facility surrounding the planet YSES-1B.
Artist rendering of the YSES-1 system, featuring a central sun-like star, YSES-1B with its dusty evasive disc (right), and YSES-1C’s atmospheric silicate clouds. Image credit: Ellis Bogut.
YSES-1 is a solar-type star located approximately 309 light-years away in the constellation of Masca.
Also referred to as TYC 8998-760-1 or 2mass J13251211-6456207, this star is roughly equivalent in mass to our Sun but is only 16.7 million years old.
The system comprises two planets, YSES-1B and YSES-1C.
These planets orbit their parent star at distances of 160 and 320 AU, making them more distant from their star than Jupiter and Saturn are from the Sun.
YSES-1B and C could exhibit redder hues compared to other exoplanets (or brown dwarfs), indicating distinct atmospheric properties.
While the system has been observed with various telescopes before the Webb, comprehensive observations were not achievable prior to the Webb program.
“Directly imaged exoplanets are the only types we can truly photograph,” stated Dr. Ebert Nazkin, a postdoctoral researcher at Trinity College Dublin.
“Typically, these exoplanets are younger, hotter from their formative layers, and astronomers observe this heat in the thermal infrared spectrum.”
Utilizing Webb’s spectroscopic capabilities, Dr. Nasedkin and his team obtained detailed spectra of the planets YSES-1B and YSES-1C.
These observations include the first direct detection of atmospheric silicate clouds on YSES-1C, validating prior hypotheses regarding its atmospheric structure.
These silicate clouds likely contain iron, which might contribute to rainfall on the planet.
Astronomers estimate that the cloud particles are less than 0.1 μm in size.
“Upon observing a smaller, more distant companion identified as YSES-1C, I detected a silicate cloud signature in the mid-infrared,” Dr. Nasedkin remarked.
“Composed primarily of sand-like particles, this represents the strongest silicate absorption feature documented in an exoplanet.”
“We believe this is connected to the planet’s youth. Younger planets tend to have slightly larger radii, and this expanded atmosphere enables clouds to absorb more light emitted by the planet.”
“We were able to employ detailed modeling to uncover the chemical makeup of these clouds as well as the size and shape of the cloud particles.”
The team also identified silicate disks surrounding YSES-1B, marking a rare observation of a substellar companion exoplanet.
This finding suggests that YSES-1B may be a relatively recently formed planet.
The discoveries enhance our understanding of the early stages of planetary formation and atmospheric development.
“The planets within the YSES-1 system are so widely separated that current formation theories cannot explain them. The discovery of distinct silicate clouds around YSES-1C and additional findings of small, hot, dusty materials around YSES-1B introduces further mystery and complexity regarding how planets form and evolve.”
The team’s results will be featured in the journal Nature this week.
____
kkw hoch et al. Silicate cloud and evasive agent disks in the YSES-1 exoplanet system. Nature Published online on June 10th, 2025. doi:10.1038/s41586-025-09174-w
Source: www.sci.news
