English: This artist' concept shows what the hot rocky exoplanet TRAPPIST-1 c could look like based on this work. TRAPPIST-1 c, the second of seven known planets in the TRAPPIST-1 system, orbits its star at a distance of 0.016 AU (about 1.5 million miles), completing one circuit in just 2.42 Earth-days. TRAPPIST-1 c is slightly larger than Earth, but has around the same density, which indicates that it must have a rocky composition. Webb’s measurement of 15-micron mid-infrared light emitted by TRAPPIST-1 c suggests that the planet has either a bare rocky surface or a very thin carbon dioxide atmosphere.

Illustrated in the background is TRAPPIST-1 b, the innermost planet in the TRAPPIST-1 system. TRAPPIST-1 b is also rocky and appears to have no substantial atmosphere.

The star, TRAPPIST-1, is an ultracool red dwarf (M dwarf) with a temperature of only 2,550 kelvins (about 4,150 degrees Fahrenheit) and a mass just 0.09 times the mass of the Sun.

This illustration is based on new data gathered by Webb’s Mid-Infrared Instrument (MIRI) as well as previous observations

from other ground- and space-based telescopes. Webb has not captured any images of the planet.