Webb Telescope Detects Methane Gas on Distant Dwarf Planet Makemake
For the first time, scientists using the James Webb Space Telescope (JWST) have detected gas surrounding a dwarf planet in the outer solar system. The findings reveal the presence of methane gas on Makemake, a celestial body approximately 890 miles (1,430 km) in diameter – about two-thirds the size of Pluto.
Previous observations, including stellar occultations, had not indicated a thick global atmosphere around Makemake, though the possibility of a tenuous atmosphere couldn’t be ruled out.Infrared observations, including those from JWST, have highlighted thermal anomalies and unusual features in Makemake’s methane ice. These observations sparked speculation about potential activity on the dwarf planet’s surface.
The detected methane gas suggests ongoing atmospheric exchange,a process where gases move between the surface and the atmosphere. Researchers are currently considering two primary explanations for this activity: sublimation – a direct transition from solid to gas, similar to what’s observed on Pluto and comets – or cryovolcanic “feathers,” where gas is ejected from the surface. Current data limitations in spectral resolution and background noise prevent a definitive conclusion between these two possibilities.
“While the temptation to connect various spectral anomalies and thermal features is strong, establishing a mechanism that drives this volatile activity remains a key step in interpreting these observations in an integrated framework,” explained Dr. Ian Wong, Staff Scientist at the Institute of Space Telescope and a co-author of the study. “Future Webb observations in higher spectral resolution will help determine whether the methane emerging from the atmosphere is thinly bound or outgassing like feathers.”
Dr.Emmanuel lellouch from the Paris Observatory, another author of the study, stated, “This finding increases the possibility that Makemake has a very weak atmosphere supported by methane sublimation.” Thier models suggest a gas temperature of around 40 Kelvin (-233 degrees Celsius) and a surface pressure of approximately 10 picobar – 100 billion times less than Earth’s atmospheric pressure and one million times weaker than Pluto’s. If confirmed, Makemake would become one of the few objects in the outer solar system known to have active surface-atmosphere exchanges.
Another possibility,according to researcher Protopapa,is that the methane is released in explosive bursts,similar to cryovolcanic feathers. In this scenario, the model indicates methane could be released at a rate of several hundred kilograms per second, comparable to the strong water plumes of Saturn’s moon Enceladus and significantly larger than the faint steam observed on Ceres.
The research team’s work combines JWST observations with detailed spectral modeling, providing new insights into the behavior of volatile-rich surfaces throughout the Trans-Neptunian region.
The findings are detailed in a paper titled “Dynamics of Rotation in Pulsasional Supernovae Instability Pair: Implications for Mass Loss and Transient Events” by Trang N.Huynh, Emmanouil Chatzopoulos, and Nageeb Times, published on September 11, 2025, in The Astrophysical Journal (DOI: 10.3847/1538-4357/ADF4E7). The data used in the study was obtained by the JWST’s Near-Infrared Spectrograph through program 1254 (Principal Investigator: Ah Parker).
