xi Aql is an orange K-type dwarf (about 1.74 solar masses, 4,841 K, 10.9 solar radii), 56.2 light-years from Earth. xi Aql b is a 1.94-Jupiter-mass companion, with an orbital period of 137 days, at 0.625 AU from its star, on an eccentric orbit (e ≈ 0.06), 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. xi Aql b circles its star within the inner habitable zone.