Exoplanet HD 189733b, artwork. This planet is a huge gas giant that orbits very close to its host star HD 189733 in the constellation of Vulpecula 63 light years away. The atmosphere has a temperature of over 1000 degrees Celsius and the planet was calculated to be a deep blue colour. The colour is thought to be due to light scattering from silicate particles raining from the sky in a sideways direction from 7,000 kilometre per hour winds. Like many exoplanet discoveries, HD 189733b was detected by the regular (periodic) dimming of the star as the planet passes in front of it.