TRAPPIST-1g is an exoplanet orbiting around the ultra-cool red dwarf star TRAPPIST-1, located 40.7 light-years away from Earth in the constellation Aquarius. The planet is one of seven planets to be discovered orbiting the star in 2017 using observations from the Spitzer Space Telescope. The exoplanet is within the optimistic habitable zone of its host star. It was found by using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured.