Recent observations by the James Webb Space Telescope reveal startling climate details of two exoplanets, TRAPPIST-1b and TRAPPIST-1c, showcasing extreme daily temperatures and freezing nights, which may hinder their prospects for habitability.
An artist’s view of an exoplanet within the TRAPPIST-1 system, which is located 38.8 light-years from Earth. These planets, similar in size and temperature to Venus and Earth, showcase unique orbital dynamics. Image credit: M. Kornmesser / ESO.
Red dwarfs, which are smaller and cooler than our Sun, account for over 75% of the stars in the Milky Way galaxy.
Research indicates that Earth-sized planets are particularly abundant around these faint stars, raising intriguing questions about the potential for life on such distinctly different worlds.
TRAPPIST-1 is one such star system currently under scrutiny.
Discovered back in 2017, this fascinating system resides 38.8 light-years away in the constellation Aquarius.
It features seven transiting planets: TRAPPIST-1b, c, d, e, f, g, and h.
These planetary bodies are either comparable to or slightly smaller than Earth and Venus, and all possess notably short orbital periods.
“The TRAPPIST-1 system is a remarkable discovery: seven planets with Earth-like masses orbiting a single star,” stated Emmeline Bolmont, an astronomer at UNIGE.
“At least three of these planets lie within the star’s habitable zone, allowing for the presence of liquid water on their surfaces.”
“This system serves as an ideal environment for comparative planetology, helping us unravel the mysteries of planetary habitability and life development around red dwarfs.”
Dr. Bolmont and her research team utilized the NASA/ESA/CSA James Webb Space Telescope to study the two inner planets, TRAPPIST-1b and TRAPPIST-1c.
“Although red dwarfs and their planetary systems are commonplace, their environments don’t guarantee the potential for life,” the team noted.
“These stars emit intense ultraviolet radiation and high-energy particles that can erode planetary atmospheres, jeopardizing any existing life forms.”
“Furthermore, planets within a red dwarf’s habitable zone orbit very closely to the star, leading to a tidal lock effect that results in one side experiencing perpetual daylight while the other is in constant darkness.”
This illustration depicts the TRAPPIST-1 star and its planets reflected on its surface. Image credit: NASA / R. Hurt / T. Pyle.
By analyzing the light emitted from the star and the two planets, astronomers accurately determined the surface temperatures on both the day and night sides of TRAPPIST-1b and TRAPPIST-1c.
Daytime temperatures exceed 200 degrees Celsius for TRAPPIST-1b and nearly 100 degrees Celsius for TRAPPIST-1c, while at night, temperatures plummet below -200 degrees Celsius.
This extreme temperature disparity implies minimal energy transfer between the planet’s sides, indicating an absence of a significant atmosphere.
Even if these planets formed with atmospheres, harsh stellar conditions would likely have stripped them away entirely.
The team concluded that the lack of dense atmospheres on TRAPPIST-1b and c supports the theory that intense stellar radiation is crucial in shaping planetary evolution in such systems.
“TRAPPIST-1 acts as a vital reference point,” Dr. Bolmont mentioned. “Our theoretical models suggest that the outer planets may retain atmospheres, unlike the inner planets, similar to Mercury’s situation near our Sun.”
“We are eager to advance our exploration of the TRAPPIST-1 system in future studies.”
The findings were published on April 3rd in Nature Astronomy.
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M. Gillon et al. “No thick atmosphere around TRAPPIST-1 b and c from JWST thermal phase curve.” Nat Astron 3 April 2026. doi: 10.1038/s41550-026-02806-9
Source: www.sci.news
