Orbiting body

In astrodynamics, an orbiting body is any physical body that orbits a more massive one, called the primary body. The orbiting body is properly referred to as the secondary body ($m_{2}$), which is less massive than the primary body ($m_{1}$).

Thus, $m_{2}<m_{1}$ or $m_{1}>m_{2}$.

Under standard assumptions in astrodynamics, the barycenter of the two bodies is a focus of both orbits.

An orbiting body may be a spacecraft (i.e. an artificial satellite) or astronomical object, such as a planet, dwarf planet, moon, moonlet, asteroid, or comet.

See also

• Barycenter
• Double planet
• Primary (astronomy)
• Satellite
• Two-body problem