Last Updated on May 21, 2026 by Staff
Astronomers using NASA’s James Webb Space Telescope or JWST have found a planet with a lot of methane in its air. This is a deal in learning about planets far away from us. The planet, called TOI-199b is about as big as Saturn. Its temperature is closer to what we have on Earth compared to giant planets.
The findings were published in The Astronomical Journal. A team of researchers led by scientists from Penn State University and NASA’s Jet Propulsion Laboratory or JPL did the study.
Gas giant planets we know of are either very cold or very hot. Some, like Jupiter and Saturn in our system, are extremely cold. They are far from the sun. Others, called “Jupiters” are very close to their stars. They get incredibly hot.
TOI-199b is different. It is a giant exoplanet. These planets are not freezing cold or scorching hot. They are valuable for studying how air forms and changes.
Researchers say this is the time they have studied the air of a temperate giant exoplanet in such detail.
Distant World
TOI-199b is then 330 light-years away from Earth. It goes around its star every 100 days.
Its air is still hotter than Earth’s. The temperature is 175 degrees Fahrenheit. Scientists say this is relatively mild compared to giant exoplanets.
The planet’s moderate temperature makes it interesting. Scientists think it may be like a stage of gas giant formation. By studying planets like TOI-199b astronomers hope to understand how planets form and change over time.
The research helps scientists compare planetary systems. Since thousands of exoplanets have been discovered astronomers now want to learn how these worlds differ from planets in our system.
The team says studying planets helps scientists improve theories about planetary formation. It may also provide clues about Earth’s air history.
Webb Technique
To study the planet’s air scientists used a method called transmission spectroscopy.
This technique works when a planet passes in front of its star from the telescope’s view. During the transit some of the star’s light goes through the planet’s air.
Different gases absorb wavelengths of light. By analyzing which wavelengths disappear scientists can identify the chemical composition of the air.
The James Webb Space Telescope is powerful for this research. It can separate light into spectra.
Researchers observed TOI-199b for 20 hours. The planet’s transit lasted seven hours. This is much longer than the transit of Jupiters.
By comparing the star’s light with the light passing through the air scientists identified chemical fingerprints.
Methane Found
The important discovery was the strong presence of methane in the planet’s air.
Scientists predicted that temperate gas giants should have methane. This is one of the clearest confirmations yet. The air absorbed wavelengths of light that matched methane’s chemical signature.
Researchers also found hints of gases including ammonia and carbon dioxide.. They need more observations to confirm their abundance.
The discovery is important because methane behaves differently depending on temperature. On hot planets methane is often destroyed. In cooler environments like TOI-199b methane can survive.
The findings help scientists test and improve models. Understanding how these gases interact could help researchers learn more about the chemistry of air including Earth’s.
Future Studies
Scientists believe this discovery is the beginning. They want to study temperate exoplanets.
The success of TOI-199b observations shows that JWST can effectively analyze atmospheres of planets that were hard to study. Researchers now hope to observe temperate giant planets.
Future studies may reveal how these planets form and how their air changes. They may also show how chemical conditions vary between planetary systems.
Researchers hope to measure the abundance of methane, ammonia and carbon dioxide in TOI-199b’s air. According to the team, studying these worlds may improve scientists’ understanding of atmospheric physics and planetary formation.
As JWST continues exploring the universe, discoveries like TOI-199b are helping astronomers learn more about planets, beyond our solar system. JWST and TOI-199b are helping us understand how planets form and survive.