Astronomy: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 ([math]\displaystyle{ m_2 }[/math]),[1] which is less massive than the primary body ([math]\displaystyle{ m_1 }[/math]).
Thus, [math]\displaystyle{ m_2 \lt m_1 }[/math] or [math]\displaystyle{ m_1 \gt m_2 }[/math].
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 a natural satellite, such as a planet, dwarf planet, moon, moonlet, asteroid, or comet.
A system of two orbiting bodies is modeled by the Two-Body Problem and a system of three orbiting bodies is modeled by the Three-Body Problem. These problems can be generalized to an N-body problem. While there are a few analytical solutions to the n-body problem, it can be reduced to a 2-body system if the secondary body stays out of other bodies' Sphere of Influence and remains in the primary body's sphere of influence.[2]
See also
References
- ↑ "Dictionary of Technical Terms for Aerospace Use". NASA. http://er.jsc.nasa.gov/SEH/s.html.
- ↑ Curtis, Howard D. (2009). Orbital Mechanics for Engineering Students, 2e. New York: Elsevier. ISBN 978-0-12-374778-5.
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