HD 235088 is an orange K-type dwarf (about 0.85 solar masses, 5,075 K, 0.77 solar radii), 41.2 light-years from Earth. HD 235088 b is a 4.2-Earth-mass planet, with an orbital period of 7.4 days, at 0.071 AU from its star, discovered in 2023 via transit. The planet was found when it crossed the face of its star, producing periodic dips in brightness that reveal its size and orbital period to space-based photometry. HD 235088 b orbits well inside Earth's distance from the Sun. At 2.0 Earth radii, HD 235088 b is a compact world comparable in size to rocky planets in our Solar System.