Planetary system

Planetary system is the general term for a star with planets and other objects in orbit around it.^[1][2] The Solar System is one of these.^[3][4][5] It is now clear that many other stars have planetary systems.

The 21st century has become a golden era of planetary system discovery. 4,801 such exoplanets in 3552 planetary systems have been discovered, including 789 multiplanet systems.^[6] Hundreds more systems are unconfirmed.

The closest confirmed system is Gliese 832 at 14.8 light years (ly) with one confirmed planet.The closest unconfirmed system is Alpha Centauri at 4.37 ly with a planet of Earth mass. The closest multi-planet system is Gliese 876 at 15.3 ly with four confirmed planets.

Of particular interest to astrobiology is the habitable zone of planetary systems. This is thought to be the region with the most potential to develop extraterrestrial life.

1. ↑ Darling, David J. (2004). The Universal Book of Astronomy, from the Andromeda Galaxy to the Zone of Avoidance. John Wiley & Sons Inc. p. 394. ISBN 978-0-471-26569-6.
2. ↑ p. 314, Collins Dictionary of Astronomy, Valerie Illingworth, London: Collins, 2000. ISBN 978-0-00-710297-6.
3. ↑ p. 382, Collins Dictionary of Astronomy.
4. ↑ p. 420, A Dictionary of Astronomy, Ian Ridpath, Oxford, New York: Oxford University Press, 2003. ISBN 978-0-19-860513-3.
5. ↑ Schneider J. Interactive Extra-solar Planets Catalog. The Extrasolar Planets Encyclopedia. [1]
6. ↑ Schneider, Jean (2011). "Interactive Extra-solar Planets Catalog". The Extrasolar Planets Encyclopedia. Retrieved 2012-07-13.