- #1

Unto

- 128

- 0

-------------------------------------------------

The first thing I did was remind myself of some important terminology:

Perihelion - closest distance to the sun/star

Aphelion - furthest distance from the sun/star.

What I'm confused is whether Aphelion is the same as the Major Semi-axis or different.. Because I've done allsorts of calculations, and I keep getting a relativistic speed which is just dumb. So my values for Aphelion are all wrong.

How would I calculate Aphelion?

I can directly determine the semi-major axis by using [tex]T^2 = a^3[/tex] and that gives me a value of 48.8AU as the semi major axis. Do I add this to the Perihelion and say that the sum is the furthest distance away from the sun? Or am I missing a crucial piece here?

I even drew a diagram, I have no way of finding the eccentricity of the orbit without Aphelion :-(.

Help please. And lastly for working out the velocity at perihelion, what is 'r' in the equation:

Assuming that 'a' is the semi major axis.