close-in planet orbiting giant star HD 167768.

This article reports the discovery of a giant planet, designated HD 167768 b, orbiting the G-type giant star HD 167768, based on radial velocity measurements from the High Dispersion Echelle Spectrograph (HIDES) at Okayama Astrophysical Observatory. The host star has a mass of approximately 1.08 solar masses, a radius of about 9.7 solar radii, and low metallicity ([Fe/H] ≈ −0.67), while the planet is a warm Jupiter with a minimum mass of 0.85 Jupiter masses, an orbital period of 20.65 days, and a semimajor axis of 0.15 au—one of the shortest orbital periods found around evolved stars with low surface gravity (log g < 3.5). The planet’s high equilibrium temperature (~1874 K) and close orbit suggest it will be engulfed by the expanding host star within roughly 0.15 billion years. Additional radial velocity signals indicate possible outer companions, though further observations are needed to confirm these. The system shares characteristics with another similar evolved star hosting a warm Jupiter, both being thick-disk, alpha-enhanced, iron-poor stars, raising questions about planet formation and survival around such stars.