Astronomers are making strides in exploring the TRAPPIST-1 system with the NASA/ESA/CSA James Webb Space Telescope, showcasing its remarkable capability to glean detailed data about the exoplanet atmospheres and effectively utilize this information. The initial findings stem from Webb’s observation of TRAPPIST-1e. Although the first four observations by Webb are not adequate to fully assess the atmosphere, scientists are using the data to refine the possibilities for these planets, including the presence of oceans similar to those on Earth and a methane-rich environment akin to Saturn’s moon Titan. Meanwhile, additional innovative observations from Webb are ongoing, revealing the unique characteristics of TRAPPIST-1e.
The Earth-sized Exoplanet TRAPPIST-1E is illustrated in the bottom right as it eclipses the flare host star in this artist’s representation of the TRAPPIST-1 system. Image credits: NASA/ESA/CSA/STSCI/JOSEPH OLMSTED, STSCI.
TRAPPIST-1 is a cool dwarf star located in the Aquarius constellation, approximately 38.8 light-years away.
The stars are only slightly larger than Jupiter and possess a mere 8% of the solar mass. They rotate rapidly and emit UV energy flares.
TRAPPIST-1 harbors seven transiting planets designated TRAPPIST-1b, c, d, e, f, g, and h.
All these planets are comparable in size to Earth and Venus, or slightly smaller, with remarkably short orbital periods: 1.51, 2.42, 4.04, 6.06, 9.21, 12.35, and 20 days, respectively.
It is possible that they could be tidally locked, meaning the same side is always facing the host star, resulting in a perpetual day and night side for each TRAPPIST-1 planet.
Among the seven planets, TRAPPIST-1E is of particular interest if it possesses an atmosphere, as its surface water is situated at a theoretically viable distance from the star.
The Space Telescope Science Institute and colleague Dr. Néstor Espinoza aimed the Webb’s NIRSpec (near-infrared spectrometer) instrument at TRAPPIST-1e during its transits in front of the star.
As starlight filters through the planet’s atmosphere, it can be partially absorbed, revealing the specific chemicals present by the resulting dips in the light spectrum that reaches Webb.
As more transits are analyzed, the clarity regarding the atmospheric composition improves.
With only four transits analyzed thus far, numerous possibilities remain open for TRAPPIST-1E, though researchers speculate that it lacks a significant primary atmosphere.
Given TRAPPIST-1’s active nature and frequent flares, it’s not unexpected that the potential hydrogen-helium atmosphere of the planet could have been stripped away by stellar radiation.
However, many planets, like Earth, develop a denser secondary atmosphere after losing their initial one.
TRAPPIST-1E may not have the capacity for this and could potentially lack a secondary atmosphere.
“We have devised a novel method to analyze Webb’s data to assess the potential atmosphere and surface conditions of TRAPPIST-1E,” said the scientist.
It appears unlikely that TRAPPIST-1e’s atmosphere is largely composed of carbon dioxide, reminiscent of Venus’s thick atmosphere or Mars’s thinner one.
Nonetheless, astronomers should be cautious, as there are no direct parallels to our solar system.
“Because TRAPPIST-1 is significantly different from our Sun, the surrounding planetary systems also exhibit notable differences, posing challenges to both observational and theoretical frameworks,” remarked Dr. Nicole Lewis of Cornell University.
“If TRAPPIST-1E has liquid water, it would require a greenhouse effect. This effect incorporates various gases, especially carbon dioxide, which help stabilize the atmosphere and maintain a warm environment on the planet.”
“A minimal greenhouse effect is beneficial, and measurements do not exclude the presence of carbon dioxide necessary to preserve water on the surface.”
The team’s analysis suggests that water could exist as global oceans or be distributed in smaller, ice-encased regions at midday.
This is due to the size of the TRAPPIST-1 planets and their orbital sizes, all of which are thought to be tidally locked, with one side perpetually facing the star and the other shrouded in darkness.
“They’re remarkable,” stated Dr. Anna Glidden, an astronomer at the Kavli Institute for Astrophysics and Space Research at MIT.
“This is an astounding measurement of starlight around an Earth-sized planet located 40 light-years away, providing insights into potential life there if conditions permit.”
“It’s thrilling to be part of this new era of exploration.”
The latest findings from Webb are discussed in two new papers published in Astrophysical Journal Letters.
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Néstor Espinoza et al. 2025. JWST-TST Dreams: NIRSpec/Prism transmission spectroscopy of the planet TRAPPIST-1e. ApJL 990, L52; doi: 10.3847/2041-8213/adf42e
Anna Glidden et al. 2025. JWST-TST Dreams: Secondary atmosphere constraints of the habitable zone planet TRAPPIST-1e. ApJL 990, L53; doi: 10.3847/2041-8213/adf62e
Source: www.sci.news
