What is the relationship between orbital semi latus rectum and angular momentum?

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Discussion Overview

The discussion revolves around the relationship between the semi latus rectum of an orbit and the angular momentum of an orbiting object. Participants are exploring the calculations and derivations related to these concepts, particularly in the context of elliptic orbits.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested, Mathematical reasoning

Main Points Raised

  • One participant expresses confusion about the semi latus rectum and its connection to angular momentum, noting discrepancies in derived values from different equations.
  • Another participant asks for clarification on the numbers and formulas used in calculations, suggesting that rounding errors or measurement uncertainties might explain the differences in results.
  • A participant mentions using equations for apoapsis and periapsis, as well as the general equation for radius in relation to eccentricity, while questioning whether these calculations impose limitations on the mass of the orbiting object.
  • One participant challenges the relevance of mass limitations in the context of the discussion, indicating a lack of understanding of how mass relates to the semi latus rectum and angular momentum.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus, as there are differing views on the implications of the calculations and the relationship between the semi latus rectum, angular momentum, and mass limitations.

Contextual Notes

Participants mention deriving the semi latus rectum from various equations and express uncertainty about the accuracy of their results, indicating potential dependencies on definitions and measurement precision.

Penguinluons
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Hi. I have recently been trying my hands at calculating a few orbits but have encountered difficulties in trying to 'understand' the semi latus rectum.

P=h^2/GM

What does it have to do with the orbiting object's angular momentum? How come I get different values when I derive it from other equations? Please help me as I need to understand this to move on to elliptic orbits.

(Note: When I derived P from other equations, I got different values but they were all quite close to each other.)
 
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Which numbers and formulas do you use to calculate the values and what are the results?
Penguinluons said:
(Note: When I derived P from other equations, I got different values but they were all quite close to each other.)
Could that come from rounding errors or measurement uncertainties?
Penguinluons said:
What does it have to do with the orbiting object's angular momentum?
Both describe some aspect of the orbital motion, what is surprising about equations involving both?
 
mfb said:
Which numbers and formulas do you use to calculate the values and what are the results?
Could that come from rounding errors or measurement uncertainties?
Both describe some aspect of the orbital motion, what is surprising about equations involving both?

I used the equations for apoapsis and periapsis as well as the general equation r=P/1+e cosθ. I tried deriving p from the semi major axis as well.e had an accuracy of about 10 digits. It was an elliptic orbit. Does this therefore place limitations on the mass of my orbiting object?
 
That does not answer my questions.

And I don't understand how you want to get limitations on a mass.
 

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