For twenty years, scientists have searched for answers about whether rocky planets orbiting distant stars could keep their air. Now, they have found one. Researchers have confirmed the first atmosphere around a rocky planet located in the habitable zone of its star. This planet, called LHS 1140 b, is about fifty light-years away from Earth. A study published in the journal Science on July 16, 2026, explains that the planet is losing a large amount of helium gas into space.
Collin Cherubim, a researcher from Harvard University, explained that an atmosphere is essential for a planet to support life as we know it. "This is the first time anyone has found an atmosphere on a rocky planet in the habitable zone of another star," Cherubim stated.
LHS 1140 b is much larger than Earth, weighing about 5.6 times as much and being almost twice as wide. It orbits its star, a quiet red dwarf, every 24.7 days. The planet is at a distance where liquid water could exist on its surface.
To find this atmosphere, scientists used a special instrument called the WINERED spectrograph in September 2024. This instrument analyzed light from the planet and detected helium atoms absorbing specific infrared light. The data showed that radiation from the star is heating the planet's upper atmosphere, causing helium to escape at a rate of about 220 tons per second. However, the planet has likely had its atmosphere for over three billion years.
Computer models suggest that while helium is in the upper atmosphere, heavier gases like carbon dioxide and water vapor might be in the lower layers. Simulations indicate LHS 1140 b could be rich in water. The planet's temperature is around 226 Kelvin, which is suitable for life.
Jason Dittmann, who first discovered the planet in 2017, noted the long process of finding worlds with the right conditions. He said that scientists have been gradually finding planets with suitable temperatures and rocky surfaces before finally confirming one with an atmosphere.
When scientists observed the planet again in 2025, the helium signal had disappeared. Shreyas Vissapragada, a co-author of the study, mentioned that the atmospheric loss seems to change over time. He described it as a rare chance to observe an alien atmosphere changing.
In contrast, a smaller rocky planet in the same system, LHS 1140 c, receives much more radiation and shows no signs of helium, suggesting its atmosphere was lost long ago.
For scientists studying life beyond Earth, LHS 1140 b is now a prime candidate. It has a rocky surface, a protective atmosphere, and temperatures that could allow liquid water. Cherubim concluded, "This planet has now become the best place to search for life outside of our solar system."