Energy
Under standard assumptions, specific orbital energy of elliptic orbit is negative and the orbital energy conservation equation (the Vis-viva equation) for this orbit can take the form:
where:
- is orbital speed of orbiting body,
- is distance of orbiting body from central body,
- is length of semi-major axis,
- is standard gravitational parameter.
Conclusions:
- For a given semi-major axis the specific orbital energy is independent of the eccentricity.
Using the virial theorem we find:
- the time-average of the specific potential energy is equal to 2ε
- the time-average of r−1 is a−1
- the time-average of the specific kinetic energy is equal to –ε
Read more about this topic: Elliptic Orbit
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—C.S. (Clive Staples)
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—Amy Laura Dombro (20th century)