BD+42 2315 is an orange K-type dwarf (about 1.38 solar masses, 4,500 K, 17.9 solar radii), 611 light-years from Earth. BD+42 2315 b is a 0.55-Jupiter-mass companion, with an orbital period of 123 days, at 0.540 AU from its star, on an eccentric orbit (e ≈ 0.73), 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. The planet's marked eccentricity suggests past scattering events or perturbations from unseen companions.