Substellar companion

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File:Wide Field Infrared Images of Gliese 229 b.jpg
Earth and Space bound observatories observe Gliese 229 and its companion, which is perhaps 20-40 Jupiter masses in size[1]

Substellar companion is a generic term for an astronomical body orbiting a star.

It can describe a celestial bodies too small to be a star, but too big to be called a planet.[1] Alternatively, it is a substellar object such as exoplanet or brown dwarf that is orbiting a star.[2] Objects as low as 8-23 Jupiter masses have been called a substellar companion.[3]

Objects orbiting a star are often called a planet below 13 Jupiter masses and brown dwarf above that.[4] Companions at that planet-brown dwarf borderline have been called Super-Jupiters, such around the star Kappa Andromedae.[5] Nevertheless, objects as small as 8 Jupiter masses have been called a brown dwarf.[6]

A substellar companion is thought to exist in the binary star system SDSS 1212.[7] Substellar companions have been confirmed by analyzing astrometric data from Hipparcos.[8]

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