Description: A planetary system is a system where one or more planets orbit one or more stars, brown dwarfs, and/or stellar remnants. Our Solar System is a planetary system with the Sun at its center. Over the past decades, thousands of planetary systems have been discovered around stars other than the Sun. A few cases are known where the central object of a planetary system is a brown dwarf, or a stellar remnant such as a neutron star or white dwarf.

Planetary systems can also be found around components of multiple star systems, such as the planet orbiting Proxima Centauri, the nearest star to the Sun and a member of a triple star system. There are also a handful of circumbinary planets, which orbit both stars of a binary star system.

The scale of planetary systems varies greatly, with some planets orbiting only a few stellar radii from their host star while others have orbits thousands of astronomical units across (where an astronomical unit corresponds to the average Earth–Sun distance).

Related Terms:

• Astronomical Unit
• Binary Star
• Brown Dwarf
• Neutron Star
• Orbit
• Proxima Centauri
• Solar System
• Stellar Remnants
• White Dwarf

Term and definition status: This term and its definition have been approved by a research astronomer and a teacher

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