An elliptical orbit with the Sun at one focus (not the center!). Positions are each 5 years apart. Planet speeds up when close to the Sun and slows down when moving away (the line between the planet and Sun sweeps out equal areas in equal intervals of time.) The planet's average distance from the Sun (orbit semimajor axis) is 25 AU, so its orbital period is 125 years (derived from 253 = 1252).

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last updated: 08 May 2001

Is this page a copy of Strobel's Astronomy Notes?

Author of original content: Nick Strobel