congratulating myself.
Call it a lucky guess, but for a Kuiper Belt/Oort Cloud object with:
Semi-major axis = 10,000 AU
I calculate:
Orbital Period = 1,000,674 years
Am I good or what! :-) But hey, you never know if there is a bunch of objects way out there that peppers the solar system with intense meteor showers every million years. Maybe some biggies too.