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Exoplanet: Kepler-9b



Kepler-9b is a gaseous exoplanet similar in size to Jupiter, but with only one-quarter of its mass. An exoplanet is any identified planet outside of our own Solar System. As of June 2013, there have been 866 exoplanets identified, located around 671 stars, nearly all within the Milky Way Galaxy. This artist's visualization of Kepler-9b shows the hypothetical bands of ammonia, sulfur and methane gases, caused by high winds churning across the planet's surface.

Kepler-9b takes a speedy 19 days to complete an orbit. By contrast, in our own Solar System, Mercury takes 88 days to orbit the Sun and is about three times as far from the Sun as Kepler-9b is from its host star. Since it orbits so close, Kepler-9b is considered a "hot Jupiter" - large like Jupiter, but hot like Mercury. Kepler-9b is in orbital resonance at a 1:2 ratio with a smaller, outer sibling. The 1:2 ratio means that for every one orbit that its sibling makes, Kepler-9b makes two orbits. This is the first verified example of two exoplanets in orbital resonance.

Launched in 2009, the Kepler spacecraft measures the light output of 150,000 stars simultaneously. The data from each star is then analyzed in order to look for periodic drops in the light curve being emitted. These drops in brightness could indicate the presence of an orbiting planet passing in front of its host star, blocking some of its light. This is called a transit. Three or more transits of equal periods are needed to catalog an object as an exoplanet candidate.

Learn more on the Kepler Mission website:

Notable Features

  • Thick bands of ammonia, sulfur and methane gases.Small, wispy storms are visible between the two adjacent bands of gas on the southern hemisphere, just south of the equator. These are caused by the bands rotating in opposing directions
  • Shares an orbital resonance with its sibling exoplanet
  • Orbits in only 19 days
  • 2,000 light-years from Earth

Related Datasets


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  • Space: Planets and Exoplanets

Dataset SourceDataset DeveloperDataset Visualization Developer Keywords
  • Exoplanet, Astronomy, Space Telescope