James Webb Space Telescope finds water and methane in atmosphere of a ‘warm Jupiter’

The James Webb Space Telescope has made a significant discovery of methane and water vapor in the atmosphere of WASP-80b, a Jupiter-like exoplanet located 163 light-years away. This detection is notable because, while water vapor has been found in a handful of exoplanetary atmospheres, methane detection using space-based spectroscopy is much less common. The discovery, involving scientists from Arizona State University and the Bay Area Environmental Research Institute, was made by observing the planet as it transited its parent red dwarf star.

WASP-80b is categorized as a warm Jupiter due to its proximity to its star, which is closer than cold Jupiters like our solar system’s Jupiter but not as close as hot Jupiters. This proximity poses a challenge for observation, akin to distinguishing a human hair from 9 miles away. By analyzing the light spectrum during the planet’s transit and eclipse, researchers can identify the unique fingerprints of molecules in the atmosphere.

The team used two models to confirm the presence of methane in WASP-80b’s atmosphere. This finding challenges previous assumptions that methane should have been detectable on similar planets by the Hubble Space Telescope. The research will further investigate what the chemical composition of WASP-80b can reveal about its formation and evolution, and how it compares to planets in our own solar system. Ultimately, this work contributes to the broader goal of searching for potential signs of biology on Earth-like planets in the future.

The study was published in the journal Nature on November 22.