| HD 209458 b
| Planet or moon information
D. Charbonneau, T. Brown, D. Latham, M. Mayor, G.W. Henry, G. Marcy, R.P. Butler, S.S. Vogt, 1999
150 light years 
| Revolves around
| Alien relevance
Has water vapor; confirms fact there is water on planets other than the Solar System
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- "We know that water vapor exists in the atmospheres of one extrasolar planet and there is good reason to believe that other extrasolar planets contain water vapor."
- —Travis Barman(source)
HD 209548 b, also nicknamed Osiris, is an exoplanet that orbits the solar analog HD 209458 in the constellation Pegasus, some 159 light-years from the Solar System.
Astronomers have detected water in the atmosphere of HD 209548 b, confirming previous theories that say water vapor should be present in the atmospheres of potential extrasolar planets.