Scientists are currently observing the intriguing exoplanet TRAPPIST-1 e using NASA’s revolutionary James Webb Space Telescope. This advanced telescope is providing unprecedented insights into the planet’s atmosphere and surface characteristics. As researchers delve into the data, they aim to address the fundamental question: “Are we alone in the universe?”
Néstor Espinoza, a leading investigator from the Space Telescope Science Institute in Baltimore, Maryland, states, “Webb’s infrared instruments are giving us more detail than we’ve ever had access to before. The initial four observations of planet e are revealing the groundwork for what we will learn as more data comes in.” Two scientific papers detailing these critical findings have been published in the Astrophysical Journal Letters.
Among the seven Earth-sized worlds orbiting the red dwarf star TRAPPIST-1, planet e stands out due to its position in the habitable zone, where conditions may allow for liquid water to exist. This zone is defined as neither too hot nor too cold, but the presence of water on the surface depends significantly on whether the planet possesses an atmosphere. That’s where the capabilities of the James Webb Space Telescope come into play.
Researchers directed the telescope's powerful NIRSpec (Near-Infrared Spectrograph) instrument at the TRAPPIST-1 system as planet e transited in front of its star. This transit allows starlight to pass through the planet's atmosphere, if one exists, resulting in specific wavelengths being absorbed. These absorption patterns can reveal the chemical components present in the atmosphere, enabling astronomers to gather vital information about TRAPPIST-1 e.
While many possibilities are still being explored, the research team is increasingly confident that TRAPPIST-1 e does not retain its original atmosphere. The star TRAPPIST-1 is highly active, frequently emitting flares that could strip away any initial hydrogen-helium atmosphere the planet may have formed with. However, like Earth, planets can develop a secondary atmosphere after losing their primary one. It remains uncertain whether TRAPPIST-1 e was able to form such an atmosphere.
According to the researchers, it is unlikely that the atmosphere of TRAPPIST-1 e is dominated by carbon dioxide, akin to the thick atmosphere of Venus or the thin atmosphere of Mars. “There are no direct parallels with our solar system,” notes Nikole Lewis, an associate professor of astronomy at Cornell University. “TRAPPIST-1 is a very different star from our Sun, which complicates our observational and theoretical assumptions.”
If liquid water exists on TRAPPIST-1 e, it would imply a greenhouse effect, where gases like carbon dioxide maintain temperature stability in the atmosphere. “A little greenhouse effect goes a long way,” states Lewis, emphasizing that adequate levels of carbon dioxide could support water on the planet’s surface. The team's analysis suggests that this water could manifest as a global ocean or be localized, potentially covering areas that remain in perpetual sunlight, surrounded by ice due to tidal locking.
Espinoza and co-principal investigator Natalie Allen from Johns Hopkins University are leading a team that is currently conducting 15 additional observations of planet e. The strategy involves timing these observations so that Webb captures both planets b and e transiting closely together. Previous observations of planet b, located nearest to TRAPPIST-1, indicate it likely lacks an atmosphere, allowing scientists to isolate signals detected during its transit. Data from planet e will be compared to ensure any atmospheric signals are accurately attributed to the planet itself.
“We are still in the early stages of discovering the incredible science we can conduct with Webb,” says Ana Glidden, a post-doctoral researcher at MIT’s Kavli Institute for Astrophysics and Space Research. “Measuring the details of starlight around Earth-sized planets 40 light-years away is fascinating, especially in considering the potential for life.”
The observations of TRAPPIST-1 e form part of the DREAMS (Deep Reconnaissance of Exoplanet Atmospheres using Multi-instrument Spectroscopy) collaboration, led by the James Webb Space Telescope Scientist Team. Webb is recognized as the world’s premier space science observatory, unlocking mysteries within our solar system and exploring distant worlds beyond our star. This international program, managed by NASA alongside ESA (European Space Agency) and CSA (Canadian Space Agency), is set to revolutionize our understanding of the universe.
To learn more about the James Webb Space Telescope and its contributions to exoplanet research, visit: NASA's official site.
