HD 231701 is a Sun-like F-type star (about 1.21 solar masses, 6,101 K, 1.53 solar radii), 109 light-years from Earth. HD 231701 b is a 1.13-Jupiter-mass companion, with an orbital period of 142 days, at 0.567 AU from its star, on an eccentric orbit (e ≈ 0.13), discovered in 2007 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.