TRAPPIST-1 e is one of seven roughly Earth-sized planets orbiting an ultra-cool red dwarf M-type star 40 light-years from Earth. With a radius of 0.9 × Earth, it completes an orbit every 6.1 days at 0.029 AU in the habitable zone’s heart. Resonant orbits and low stellar flux support potential rocky surfaces with atmospheres and liquid water. This multi-planet laboratory offers invaluable insights into habitability around diminutive stars. It shines eternally in the Galactic Codex as a prime archetype of compact habitable-zone systems.
