TRAPPIST-1e

TRAPPIST-1e is a rocky, close-to-Earth-sized exoplanet orbiting within the habitable zone around the ultra-cool red dwarf star TRAPPIST-1, located 40.7 light-years (12.5 parsecs; 385 trillion kilometers; 239 trillion miles) away from Earth in the constellation of Aquarius. Astronomers used the transit method to find the exoplanet, a method that measures the dimming of a star when a planet crosses in front of it. The planet was one of seven planets discovered orbiting the star using observations from the Spitzer Space Telescope. Three of seven planets (e, f, and g) are in the habitable zone. TRAPPIST-1e is similar to Earth's mass, radius, density, gravity, temperature, and stellar flux. It is also confirmed that TRAPPIST-1e lacks a cloud-free hydrogen-dominated atmosphere, meaning that if the planet has an atmosphere it is more likely to have a compact atmosphere like the terrestrial planets in the Solar System. In November 2018, researchers determined that of the seven exoplanets in the multi-planetary system, TRAPPIST-1e has the best chance of being an Earth-like ocean planet, and the one most worthy of further study regarding habitability. The most recent observation in 2025 was unable to conclude with confidence if there was an atmosphere or not, though it could rule out certain atmosphere scenarios.