HD 120084 is a star with an orbiting exoplanet in the northern constellation of Ursa Minor. With an apparent magnitude of 5.91, it is just visible to the naked eye in suburban skies.[1] The distance to this system is 339 light years based on parallax measurements, but it is drifting closer to the Sun with a radial velocity of −9 km/s.
This is an evolved G-type giant star, a yellow giant, with a stellar classification of G7III. It has an effective temperature of around 4892 K, with around 1.9 times the mass, 43 times the luminosity and 8 times the radius of the Sun.
A planet with at least 4.5 times the mass of Jupiter and a highly eccentric orbit (with an eccentricity of 0.66) was discovered by precisely measuring the radial velocity of the star in 2013. With an average distance of 4.5 AU from its star, this planet has one of the most eccentric orbits discovered. In 2022, the inclination and true mass of HD 120084 b were measured via astrometry.