HD 171238 is a Sun-like G-type star (about 0.92 solar masses, 5,467 K), 44.8 light-years from Earth. HD 171238 b is a 8.80-Jupiter-mass companion, with an orbital period of 4.15 years, at 2.518 AU from its star, on an eccentric orbit (e ≈ 0.36), discovered in 2009 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.