Pluto sometimes approaches nearer to the sun than Saturn because Pluto's orbit is quite eccentric?

Answer 1

Pluto sometimes approaches nearer to the sun than Saturn, because Pluto's orbit is elliptical, somewhat like a squashed circle. Pluto's orbit is also highly inclined at an angle of 17 degrees. Pluto takes 248-years to orbit the sun once, and at its closest point, comes within 30-astronomical units of the sun.

Answer 2

Yes, Pluto's orbit is highly elliptical, which causes it to sometimes come closer to the sun than Saturn. This orbital eccentricity is one of the reasons why Pluto was classified as a dwarf planet rather than a full-fledged planet within our solar system.