Exoplanet HD 189733b and its parent star, illustration. HD 189733 b is an exoplanet approximately 63 light-years away in the constellation of Vulpecula. It was discovered orbiting the star HD 189733 A in 2005, when astronomers observed the planet transiting across the face of the star. HD 189733 b orbits its host star once every 2.2 days at an orbital speed of 152.5 kilometres per second, making it a hot Jupiter with little prospect for extraterrestrial life. Being the closest transiting hot Jupiter to Earth, HD 189733 b is a subject for extensive atmospheric examination.