Circumtriple planet
Planet that orbits three stars
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Examples
The only confirmed circumtriple planet, as of 2024[update], is Gliese 900 b (CWISE J233531.55+014219.6). It was found to be gravitationally bound to the Gliese 900 system in 2024, at a projected separation of 12,000 au,[4] thus becoming the planet with the longest orbital period.
As of 2021[update], it is suspected that the star system GW Orionis, which contains a large disk of dust and gases and is about 1,300 light years away from Earth, has a circumtriple planet within a gap observed in the dust cloud.[5] The planet itself has not been seen but its influence may explain gravitational oddities within the star system.[6] By using computer modeling, some scientists believe that a Jupiter-sized planet may be able to explain the star system's rings and strange behavior.[3]
In 2022, tentative evidence of a very small planet was found around the triple system PSR J0337+1715.[7] In 2024, additional data allowed the planet's mass to be constrained to 0.0041±0.003 M🜨, making it one of the smallest objects directly detected outside the Solar System so far.[1] However, in 2025 it was suggested that the planet is not real, but instead an artifact of "red noise", which is a product of variability within the pulsar in the system.[8]
Three stars of GG Tau A are surrounded in protoplanetary disks, which can evolve into a circumtriple planet.[9][10]
In fiction
A circumtriple planet is prominently featured in the Remembrance of Earth's Past book series. In the series, the planet of Trisolaris orbits a three-star system, and the chaotic nature of the system drives the native species of the planet to seek refuge on Earth, which has a comparatively more "stable" one-star system.[11]