HD 191939 is a Sun-like G-type star (about 0.81 solar masses, 5,348 K, 0.94 solar radii), 53.6 light-years from Earth. The system hosts 6 confirmed planets on orbits ranging from 8.9 days to 7.93 years. With 6 confirmed worlds, HD 191939 is a densely packed system whose resonances, spacing, and formation history are active research topics. Mutual gravitational tugs between the planets can slowly reshape their orbits, preserving clues to the system's assembly. HD 191939 b orbits well inside Earth's distance from the Sun. Its low mass makes HD 191939 b a Neptune- or super-Earth-class world rather than a gas giant.