Co-orbital configuration
（重定向自Trojan Planets）
![Trojan points are the points labelled L4 and L5, highlighted in red, on the orbital path of the secondary object (blue), around the primary object (yellow).](/Images/godic/202502/17/Lagrange_very_massive.svg4253.png")
![Rotating-frame depiction of the horseshoe exchange orbits of Janus and Epimetheus](/Images/godic/202502/17/File-Epimetheus-Janus_Orbit4253.png")
In astronomy, a co-orbital configuration is a configuration of two or more astronomical objects (such as asteroids, moons, or planets) orbiting at the same, or very similar, distance from their primary, i.e. they are in a 1:1 mean-motion resonance. (or 1:−1 if orbiting in opposite directions)