HD 209458 is a star located about 159 light-years away in the constellation of Pegasus. It is a G-type main-sequence star, similar to our Sun, and is known for hosting an exoplanet named HD 209458 b, which was one of the first exoplanets discovered to transit its star. HD 209458 b is a gas giant, often referred to as a "hot Jupiter" due to its close orbit around the star, completing a full revolution in just about 3.5 days. This proximity results in extremely high temperatures, making it an interesting subject for studying atmospheric conditions and the potential for future discoveries in exoplanet research.