Mechanics - OrbitsWatch
An astroid is observed to orbit the Sun in an elliptical orbit. If theta is the angle between the line joining the Sun at the astroids perihelion and the astroid in orbit, an astronomer finds that when theta = Pi/3 the astroid is 2.3 AU from the Sun. The astronomer also notes that the period of the orbits 8 years.
What distance is the astroid from the Sun at aphelion?
So I can work out 'a' semi-major axis using t=a^(3/2).
And I know the aphelion is at 'a+ae' but how do I find 'e' eccentricity?