Discovery of HD 189733 b

HD 189733 b is a hot Jupiter, a gas giant that orbits very close to its star, completing an orbit in about two days. Its star, HD 189733, is a K-type dwarf in the constellation Vulpecula about sixty-three light-years from Earth, and the planet was discovered by the transit method. Because it is bright and close, it became one of the most studied exoplanets. Observations detected water vapor, carbon dioxide and methane in its atmosphere, and the Spitzer telescope produced one of the first temperature maps of an exoplanet. In 2013 Hubble observations suggested that the planet is deep blue in color, the first time the color of an exoplanet was measured, though the color likely comes from clouds of silicate particles and not from oceans.

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