How to calculate perihelion precession

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Discussion Overview

The discussion focuses on calculating perihelion precession, particularly in the context of a hypothetical space probe orbiting the Sun. Participants explore the effects of heat emission on the probe's motion and how this might influence its perihelion precession.

Discussion Character

  • Exploratory, Technical explanation, Homework-related

Main Points Raised

  • One participant proposes a scenario where a space probe emits heat in the direction of its motion, suggesting this could create a resistance effect when moving from aphelion to perihelion and an acceleration effect after passing perihelion.
  • Another participant mentions Lagrange's planetary equations as a method to analyze the orbit elements influenced by forces acting on the probe.
  • A further contribution clarifies that these equations can be used to derive long-term behavior by averaging over the orbital period.
  • One participant expresses difficulty with the mathematical concepts and requests an example to illustrate the calculations involved.
  • Another participant offers a reward for someone willing to provide a detailed example of the calculation process.

Areas of Agreement / Disagreement

Participants have not reached a consensus on the calculation methods or the implications of the proposed scenario. There are multiple viewpoints regarding the approach to calculating perihelion precession.

Contextual Notes

The discussion includes assumptions about the effects of heat emission on motion, which may not be universally accepted. The mathematical complexity of the proposed methods and the specific conditions under which they apply remain unresolved.

Who May Find This Useful

Readers interested in astrodynamics, orbital mechanics, and the effects of non-conventional forces on celestial orbits may find this discussion relevant.

Bjarne
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Let’s say that a space probe orbiting the Sun in an elliptical orbit prove would emit heat towards the motion direction., and hence causing resistance against motion.
Let’s say it would happen only when it was moving from aphelion towards perihelion, - and that the motion resistance is 1E-9 m/s.
After passing Perihelion the opposite did happen, instead of resistance the heat escape would be turned to acceleration, also 1E-9 m/s.

I believe this would cause the space prove to get its own perihelion precession anomaly.

How can a such be calculated ?
 
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Lagrange's planetary equations, which you can find in most astrodynamics texts.
 
Those are equations for the object's orbit elements as functions of the forces on it. One can find equations for long-term behavior by averaging over orbit times.
 
This math is above my head, can someone show an example?
 
I am willing to reward the one that will spend time on showing an example of calculation.
 

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