The James Webb Space Telescope (JWST) has embarked on an ambitious mission to explore the exoplanet TRAPPIST-1 e, providing unprecedented insight into its atmospheric and surface conditions.
This investigation is crucial as scientists contemplate the question of whether life may exist beyond Earth.
Néstor Espinoza from the Space Telescope Science Institute in Baltimore, Maryland, a principal investigator on the research team, stated, “Webb’s infrared instruments are giving us more detail than we’ve ever had access to before.
The initial four observations we’ve conducted on planet e are revealing the framework of what to expect as more data becomes available.”
Two scientific papers detailing the early results have been published in the Astrophysical Journal Letters.
TRAPPIST-1, a red dwarf star, hosts a system of seven Earth-sized planets, and planet e is particularly intriguing.
It orbits at a distance theoretically suitable for the existence of liquid water—an essential ingredient for life—if it possesses an atmosphere.
To investigate this, researchers utilized the NIRSpec (Near-Infrared Spectrograph) aboard Webb, focusing on the star during planet e’s transit.
When TRAPPIST-1 e passed in front of its star, the starlight filtering through the planet’s atmosphere provided critical data.
This starlight is partially absorbed by atmospheric gases, and the resulting alterations in the light spectrum help scientists identify the chemical makeup of the atmosphere.
With additional observations planned, researchers hope to clarify the atmospheric composition further.
Despite the early opportunities for exploration, initial analyses suggest that TRAPPIST-1 e is unlikely to retain its original, primary atmosphere.
The star’s activity, characterized by numerous stellar flares, likely stripped away any hydrogen-helium atmosphere that may have been present at the planet’s formation.
Interestingly, some planets, like Earth, develop a secondary atmosphere after losing their initial one.
However, researchers speculate that planet e either could not form such an atmosphere or still has yet to develop one.
This uncertainty means scientists are exploring a range of possibilities regarding the planet’s atmospheric conditions and surface environments.
The researchers also pointed out that while an atmosphere predominated by carbon dioxide, akin to that of Venus, is unlikely, TRAPPIST-1’s distinct characteristics challenge existing assumptions.
Nikole Lewis, an associate professor of astronomy at Cornell University and part of the research team, noted, “TRAPPIST-1 is a very different star from our Sun, and so the planetary system around it is also very different, which challenges both our observational and theoretical assumptions.”
Should liquid water exist on TRAPPIST-1 e, it would likely create a greenhouse effect, with gases like carbon dioxide stabilizing and warming the atmosphere.
Lewis emphasized, “A little greenhouse effect goes a long way,” indicating that while the evidence does not rule out sufficient carbon dioxide for water presence, various scenarios involving water have emerged from their analysis.
One possibility includes a global ocean or a smaller area of liquid water situated on the side perpetually facing the star, surrounded by ice.
This scenario is plausible due to the tidal locking nature of the TRAPPIST-1 planets, where one side consistently faces the host star while the opposing side remains in darkness.
In pursuit of more information, Espinoza and co-principal investigator Natalie Allen from Johns Hopkins University are leading a team in observing TRAPPIST-1 e further.
They have devised a novel strategy involving timing observations so that both planets b and e transit the star in quick succession.
With planet b, which orbits closest to TRAPPIST-1, likely being a bare rock without an atmosphere, astronomers are confident that signals detected during its transit can be attributed solely to the star.
As a result, because planet e transits shortly thereafter, this method minimizes the complications arising from the star’s variability.
The scientists aim to compare the data collected from both planets, allowing any chemical signatures visible only in planet e’s spectrum to be attributed explicitly to its atmosphere.
Ana Glidden, a post-doctoral researcher at the Massachusetts Institute of Technology’s Kavli Institute for Astrophysics and Space Research, who leads the research on potential atmospheres for TRAPPIST-1 e, remarked, “We are really still in the early stages of learning what kind of amazing science we can do with Webb.
It’s incredible to measure the details of starlight around Earth-sized planets 40 light-years away and learn what it might be like there if life could be possible.
We’re in a new age of exploration that’s very exciting to be a part of.”
The first four transits of TRAPPIST-1 e analyzed in the papers were captured by the JWST Telescope Scientist Team’s DREAMS (Deep Reconnaissance of Exoplanet Atmospheres using Multi-instrument Spectroscopy) collaboration.
The James Webb Space Telescope, renowned as the premier space science observatory, is tasked with solving mysteries within our solar system, examining distant worlds around other stars, and investigating the structures and origins of the universe and our place in it.
The Webb project is an international collaboration led by NASA along with partners ESA (European Space Agency) and CSA (Canadian Space Agency).
For those interested in learning more about Webb and its groundbreaking research efforts, additional information can be found at https://science.nasa.gov/webb.
image source from：science
