Astronomers Discover Potential Atmosphere on Earth-Sized Exoplanet

New research has revealed the potential for an atmosphere surrounding an Earth-sized exoplanet, known as TRAPPIST-1e, located approximately 40 light-years from Earth. A team from the University of St Andrews published their findings in the Astrophysical Journal Letters, indicating that the James Webb Space Telescope (JWST) is advancing toward confirming whether TRAPPIST-1e possesses an atmosphere. This research represents the first focused search for atmospheric conditions and surface habitability on TRAPPIST-1e utilizing the JWST.

As the fourth planet in the TRAPPIST-1 red dwarf star system, TRAPPIST-1e orbits within its star’s habitable zone. The planet has garnered significant interest due to the theoretical viability of liquid water, contingent on the presence of an atmosphere. Initial results from the study suggest several scenarios, including the intriguing possibility of an atmosphere.

Research Breakthroughs and Challenges

Dr. Ryan MacDonald, a lecturer in extrasolar planets at the University of St Andrews, stated, “TRAPPIST-1e has long been considered one of the best habitable zone planets to search for an atmosphere.” In 2023, however, the team faced challenges when their observations revealed that the red dwarf star’s activity was contaminating their data, complicating their search for an atmosphere.

To address this, the researchers directed the JWST’s powerful NIRSpec (Near-Infrared Spectrograph) instrument at TRAPPIST-1e during its transit in front of the star. As starlight passes through any existing atmosphere, it may be partially absorbed, resulting in changes to the light spectrum that the JWST detects. This information could reveal the chemical composition of the planet’s atmosphere. Nevertheless, the researchers also needed to account for starspots, which are disturbances caused by magnetic fields on the star’s surface.

The team dedicated over a year to meticulously correcting the data for contamination from the star before focusing on the planet’s atmospheric characteristics.

Future Observations and Significance

Dr. MacDonald highlighted two potential explanations for their initial observations. “The most exciting possibility is that TRAPPIST-1e could have a so-called secondary atmosphere containing heavy gases like nitrogen. But our initial observations cannot yet rule out a bare rock with no atmosphere.”

Looking ahead, the researchers are securing additional observations with the JWST to deepen their search for an atmosphere on TRAPPIST-1e. With each new transit analyzed, the clarity regarding the atmospheric contents will improve. Dr. MacDonald noted, “In the coming years, we will go from four JWST observations of TRAPPIST-1e to nearly 20. We finally have the telescope and tools to search for habitable conditions in other star systems, which makes today one of the most exciting times for astronomy.”

This research not only enhances our understanding of TRAPPIST-1e but also contributes significantly to the broader quest for potentially habitable worlds beyond our solar system.