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.
One year on Mars is approximately 687 Earth days long. A day on Mars, known as a sol, is about 24 hours and 39 minutes. This means a year on Mars is almost twice as long as an Earth year in terms of days.
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.
MARS
88 (Earth) days.