About this world
TRAPPIST-1 c is an Earth-sized planet orbiting TRAPPIST-1, a cool red dwarf (type M8.0V) 40.5 light-years from Earth. It is about 1.1 times the size of Earth and holds 1.3 Earth masses. It completes an orbit every 2.42 days at 0.016 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 340 K (67 °C): too cold for liquid water on its surface. By the "cosmic shoreline", its star has probably stripped its atmosphere away, leaving bare rock. Its atmosphere has already been studied: 17 spectroscopic observations, all of them with the James Webb Space Telescope.
It was discovered in 2016 by transit with La Silla Observatory. A planet crosses its star and dims it by a tiny, periodic fraction. TRAPPIST-1 has 7 known planets; the others are TRAPPIST-1 b, TRAPPIST-1 d, TRAPPIST-1 e, TRAPPIST-1 f, TRAPPIST-1 g and TRAPPIST-1 h.