Halley's comet eccentricity

orbitsnerd

1. The problem statement, all variables and given/known data
I am given Rp=.6AU and need to find the eccentricity.


2. Relevant equations
Rp=a(1-e)


3. The attempt at a solution
I can find what Halley's comet eccentricity is (0.967) but I need to actually calculate it. What is the equation I need? I know I need to know Ra, or a, or p.

gabbagabbahey

Are you told the period of Haley's orbit?

orbitsnerd

yes, I guess I was and overlooked it. It was stated in 1910-1986, so 76 years. I can now find a and solve the problem. Thanks!