Homework Help: Kepler's law i think. I need help

1. Nov 24, 2008

dswatson

The asteroid Icarus, discovered in 1949, was so named because its highly eccentric elliptical orbit brings it close to the sun at perihelion. The eccentricity e of an ellipse is defined by the relation rp=a(1-e) where rp is the perihelion distance and a is the semi-major axis. Icarus has an eccentricity of 0.83 and a period of 1.1y.

a)Determine the semi-major axis of the orbit of Icarus.

b)Determine the perihelion and aphelion distances of thie orbit of Icarus.

2. Nov 24, 2008

mgb_phys

a, the semi major axis comes straight from keplers third law

b, The sun is at one focus of the elipse, so if you know 'e' and 'a' the other parts of the elipse drop out.

Last edited: Nov 24, 2008