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

AI Thread Summary
The discussion focuses on the relationship between the semi latus rectum and angular momentum in orbital mechanics. The semi latus rectum is defined by the equation P = h²/GM, where h represents angular momentum, G is the gravitational constant, and M is the mass of the central body. The participant is struggling with inconsistencies in derived values for P from different equations, questioning whether these discrepancies arise from rounding errors or measurement uncertainties. They also inquire about the implications of these calculations for understanding elliptic orbits and the potential limitations on the mass of the orbiting object. The conversation emphasizes the need for clarity in the mathematical relationships governing orbital motion.
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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