A circumtriple planet is a celestial mass that is hypothesized to be orbiting not only a single star but three stars at the same time.[1] Scientists observing the star system GW Ori, which is a huge disk of dust and gases about 1,300 light years away from Earth, suspect that there may be a circumtriple planet orbiting the three stars.[2] They observed a gap in the vast dust cloud and they hypothesize that there may be a planet in this gap.[2] The planet itself has not been seen but its influence may explain gravitational oddities within the star system.[3] 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, according to one account.[4] If so, this may be the first known example of a circumtriple planet in the universe.[4]
In 2022, evidence of a very small planet was found around the triple system PSR J0337+1715.[5] 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.[6]
In 2024, the substellar object CWISE J235827.96–521813.4 was detected to be bound to the Gliese 900 triple star system at a distance of 12000AU,[7] thus becoming the planet with the longest orbital period and first confirmed circumtriple planet.
If a circumtriple planet exists, it will be an extremely rare phenomenon in the universe.[4] It could add to human understanding of how planets form.[3]
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.[8]
References
^Kelly Kizer Whitt (October 1, 2021). "Circumtriple planet suspected: a planet orbiting 3 stars". EarthSky.org. Retrieved October 6, 2021. ...The suspected planets are not the first found in triple star systems. But planets found in those other systems orbited just one of the stars, not all three stars....