page_title: Sphere of influence (astrodynamics)
section_title: Table of selected SOI radii
hierarchical_section_title: Sphere of influence (astrodynamics) / Table of selected SOI radii
caption_attribution_description: Slovenčina: Dependence of Sphere of influence on the ratio m/M
context_page_description: A sphere of influence in astrodynamics and astronomy is the oblate-spheroid-shaped region around a celestial body where the primary gravitational influence on an orbiting object is that body. This is usually used to describe the areas in the Solar System where planets dominate the orbits of surrounding objects such as moons, despite the presence of the much more massive but distant Sun. In the patched conic approximation, used in estimating the trajectories of bodies moving between the neighbourhoods of different masses using a two body approximation, ellipses and hyperbolae, the SOI is taken as the boundary where the trajectory switches which mass field it is influenced by.
  The general equation describing the radius of the sphere of a planet:
  where
  is the semimajor axis of the smaller object's orbit around the larger body.
  and are the masses of the smaller and the larger object, respectively.
  In the patched conic approximation, once an object leaves the planet's SOI, the primary/only gravitational influence is the Sun.
context_section_description: The table shows the values of the sphere of gravity of the bodies of the solar system in relation to the Sun (with the exception of the Moon which is reported relative to Earth):
caption: Dependence of Sphere of influence rSOI/a on the ratio m/M
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