DMPP-4 is a Sun-like F-type star (about 1.25 solar masses, 6,400 K, 1.38 solar radii), 25.3 light-years from Earth. DMPP-4 b is a 12.2-Earth-mass planet, with an orbital period of 3.5 days, at 0.049 AU from its star, on an eccentric orbit (e ≈ 0.06), discovered in 2023 via radial velocity. The planet betrayed itself through the star's reflex motion — a technique that first revealed worlds around Sun-like stars in the 1990s and remains a workhorse of exoplanet discovery. DMPP-4 b skims its star closer than Mercury orbits the Sun.