It is 9 months
The dwarf planet Pluto is the planet with a year 248 earth years long.
The dwarf planet Haumea is the planet with a year 280 earth years long.
The dwarf planet Makemake is the planet with a year 310 earth years long.
224.7 Earth days
0.2408 of an Earth year.
It is one mercury year long
356 days.......
Mercury is the planet with an 88-day year.
Mars.
The dwarf planet Eris best fits this description, with a year about 561 years long.
neptune