exoplanet
Sign in to savealt=Timelapse of exoplanets orbit motion|thumb|upright=1.5|Four exoplanets of the HR 8799 system imaged by the [[W. M. Keck Observatory over the course of seven years. Motion is interpolated from annual observations.]] thumb|295x295px|Comparison of the size of exoplanets orbiting Kepler-37 to Mercury, Mars and Earth An exoplanet or extrasolar planet is a planet outside of the Solar System. The first confirmed detection of an exoplanet was in 1992 around a pulsar, and the first detection around a main-sequence star was in 1995. A different planet, first detected in 1988, was confirmed in 2003.
AI overview
An exoplanet is a planet that orbits a star outside our Solar System. Scientists have been detecting exoplanets since the early 1990s, which has expanded our understanding of how common planets may be throughout the universe.
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Article
42 sectionsContents
- Definition
- IAU
- Alternatives
- Confirmation
- Nomenclature
- History of detection
- Early speculations
- Discredited claims
- Confirmed discoveries
- Candidate discoveries
- Detection methods
- Direct imaging
- Indirect methods
- Formation and evolution
- Planet-hosting stars
- Orbital and physical parameters
- General features
- Color and brightness
- Magnetic field
- Plate tectonics
- Volcanism
- Rings
- Moons
- Atmospheres
- Comet-like tails
- Insolation pattern
- Surface
- Surface composition
- Surface temperature
- Habitability
- Habitable zone
- Ice ages and snowball states
- Tidal heating
- Potentially habitable planets
- Earth-size planets
- Planetary system
- Search projects
- See also
- Notes
- References
- Further reading
- External links
alt=Timelapse of exoplanets orbit motion|thumb|upright=1.5|Four exoplanets of the HR 8799 system imaged by the [[W. M. Keck Observatory over the course of seven years. Motion is interpolated from annual observations.]] thumb|295x295px|Comparison of the size of exoplanets orbiting Kepler-37 to Mercury, Mars and Earth An exoplanet or extrasolar planet is a planet outside of the Solar System. The first confirmed detection of an exoplanet was in 1992 around a pulsar, and the first detection around a main-sequence star was in 1995. A different planet, first detected in 1988, was confirmed in 2003. In 2016, it was recognized that the first possible evidence of an exoplanet had been noted in 1917.
There are many methods of detecting exoplanets. Transit photometry and Doppler spectroscopy have found the most, but these methods suffer from a clear observational bias favoring the detection of planets near the star; thus, 85% of the exoplanets detected are inside the tidal locking zone. About 1 in 5 Sun-like stars are estimated to have an "Earth-sized" planet in the habitable zone. Assuming there are 200 billion stars in the Milky Way, it can be hypothesized that there are 11 billion potentially habitable Earth-sized planets in the Milky Way, rising to 40 billion if planets orbiting the numerous red dwarfs are included.