Pluto’s first observations made by NASA’s James Webb spatial telescope revealed surprising phenomena: seasonal changes on the surface, with redistribution of volatile ice, and even Pluto’s atmosphere molecules being attracted to its main moon, Piconte
This process, unique in our solar system, is as if Pluto’s atmosphere “leaked” to the north and southern poles of Caronte.
These details were described in a series of studies published this spring by an international team of scientists.
A University of California researcher in Santa Cruz, Xi Zhang is particularly animated by the results.
A recent article, published June 2 in the journal Nature Astronomy, confirmed ideas he proposed in 2017, based on the historic passage of the New Horizons probe for Pluto in 2015, which gave scientists the closest vision of this distant world.
At that time, Pluto was no longer considered a planet, but a “dwarf planet” due to cosmic criteria he did not meet.
A “crazy” idea
After New Horizons passed, Zhang published a study suggesting that Pluto’s atmosphere was dominated by mist particles, something that made it completely different from other atmospheres in the solar system.
He proposed that these mist particles warm and cool, controlling the energy balance in Pluto’s atmosphere.
“It was a crazy idea,” said Zhang, remembering that many colleagues doubted at the time.
But he and his co -authors made a clear forecast: if the mist was cooling Pluto, it should issue a strong medium infrared radiation, something that could be observed with a potent telescope.
This moment arrived on December 25, 2021, when James Webb was released.
Zhang said the new study was motivated by his hypothesis of 2017.
“We were very proud because it confirmed our forecast,” he said.
“In planetary science, it is not common for a hypothesis to be confirmed so fast, in just a few years.
We feel lucky and excited.”
Nebulous conditions
The New Horizons passage in 2015 revealed that Pluto has amazing landscapes, with mountains, valleys, nitrogen (N”) and methane (CH”) glaciers, and an atmosphere rich in volatile compounds such as nitrogen, methane and carbon monoxide.
The mist in the atmosphere of Pluto is formed by chemical reactions between methane and nitrogen, similar to mist in
Moon Titan, from Saturn.
Already dear is different: it has no atmosphere and its surface is mainly covered with water ice mixed with ammonia compounds.
Their darker and reddish polar regions are probably formed by methane molecules that escape the atmosphere of Pluto and deposit there.
James Webb’s new observations brought a clearer view of this distant system.
For the first time, the Telescope Miri instrument measured the infrared thermal emission of Pluto and is lucky separately, in wavelengths of 18, 21 and 25 micrometers.
In May 2023, James Webb also captured a high quality infrared spectrum (from 4.9 to 27 micrometers) of the Pluto atmosphere, a track never explored before due to the limitation of previous instruments.
These data revealed an unexpected chemical richness, helping to better understand the atmospheric processes and the origin of Pluto’s ice.
Cosmic clues in the mist
James Webb data also showed variations in the thermal radiation of Pluto’s surface and Charte during its rotation.
Comparing this information with thermal models, scientists were able to determine properties such as thermal inertia, emissivity and temperature of different regions.
These characteristics explain how gelles are distributed in Pluto and how molecules of their atmosphere “travel” to Charte.
The new data confirmed another forecast by Linfeng Wan, a former doctoral student of Zhang and co-author of the article.
James Webb’s observations corresponded to the 2023 forecast on the amplitude of the Caronte rotational light curve.
“Pluto is in a unique position to understand how planetary atmospheres behave,” explained Zhang.
“This helps us expand our knowledge about how the mist acts in extreme environments.” He pointed out that moons like Triton, by Neptune, and Titan, from Saturn, also have atmospheres with a similar mist, which suggests that we need to rethink the role of these particles.
Zhang also pointed out a deeper connection: “Before oxygen accumulated in the earth’s atmosphere, about 2.4 billion years ago, life has existed.
But the earth’s atmosphere was very different – without oxygen, with a lot of nitrogen and hydrocarbones.
Studying the mist and chemistry of Pluto, we can have new clues about the conditions that made Earth inhabited.”
In the Nature Astronomy article, Zhang and Wan contributed to theoretical models to interpret James Webb data, calculating thermal spectra and reevaluating the cooling rates of Pluto’s atmosphere.
The team behind the studies was led by researchers from the Instrumentation and Research Laboratory in Astrophysics, the Paris Observatory, and the University of Reims Champagne-Argenne.
Published in 06/08/2025 22h04
Text adapted by AI (Grok) and translated via Google API in the English version. Images from public image libraries or credits in the caption. Information about DOI, author and institution can be found in the body of the article.
Reference article:
| Geoprocessing Drone Systems HPC |
| ERP and CRM Systems Mobile Systems AI |