TRAPPIST-1 planetary system, illustration

TRAPPIST-1 planetary system. Computer illustration showing what the TRAPPIST-1 planetary system may look like, based on available data about the planets' diameters, masses and distances from their host star (far left), as of February 2018. TRAPPIST-1 is an ultra-cool red dwarf star. It is slightly larger but much more massive than the planet Jupiter and lies around 39.6 light-years from the Sun, in the constellation Aquarius. The planetary system consists of 7 terrestrial planets that orbit very close to their star - a larger number than detected in any other planetary system. All are thought to be rocky and some could contain significant amounts of water. The system was named after the TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope) telescope that was used to study it, along with NASA's Spitzer and Kepler space telescopes.