TRAPPIST-1h

TRAPPIST-1h is the outermost planet in the TRAPPIST-1 system, located about 40 light-years away from Earth. It resides in the constellation of Aquarius. The system is named after the TRAPPIST (Transiting Planets and Planetesimals Small Telescope) in Chile.

Because it orbits very close to its cool host star, TRAPPIST-1h completes a full orbit in approximately 18.7 Earth days. This makes its "year" less than three weeks long. Despite this close proximity, it receives very little energy from the dim red dwarf star.

Scientists believe TRAPPIST-1h is likely too cold to support liquid surface water on its own. It receives less stellar energy than Mars does from our Sun, relying on a strong greenhouse effect to maintain habitable temperatures. However, tidal heating could potentially warm its interior.

The TRAPPIST-1 system was first announced in 2016, but the full confirmation of its seven planets, including TRAPPIST-1h, came in early 2017. NASA's Spitzer Space Telescope played a crucial role in observing the planets transiting the star. This discovery made it the largest known system of Earth-sized planets.