Comparison of the largest TNOs
by Wm. Robert Johnston
last updated 19 July 2015
The image below compares the sizes of the largest outer solar system objects. It includes:
- the Earth, the Moon, and Mercury (the smallest planet other than Pluto), for reference;
- the three largest asteroids: (1) Ceres, (2) Pallas, and (4) Vesta;
- Triton, the largest moon of Neptune;
- Pluto, its large moon Charon, and its smaller moons Hydra, Nix, Kerberos and Styx;
- (136199) Eris and its moon Dysnomia;
- (136108) Haumea and its moon Hi'iaka and Namaka;
- (136472) Makemake;
- the distant object (90377) Sedna;
- the 46 other known trans-Neptunian objects that are at least 500 km in diameter--at least as large as the three largest asteroids--and their 7 known moons;
- the ringed object (10199) Chariklo;
- the triple object (47171) 1999 TC36; and
- the U.S. state of Texas for comparison.
Relative sizes, brightnesses, and colors are shown.
As of 2015, the IAU classifications for these objects include:
- planet: Earth, Mercury
- dwarf planet: Pluto, Ceres, Eris, Makemake, Haumea; status pending for:
- trans-Neptunian objects (20000) Varuna, (28978) Ixion, (55565) 2002 AW197, (50000) Quaoar, (55636) 2002 TX300, (90377) Sedna, (90482) Orcus,
- asteroids (2) Pallas, (4) Vesta, and (10) Hygiea (not shown)
- small solar system body: includes remaining asteroids and trans-Neptunian objects
- natural satellite: Moon, Triton (both moons of planets), Charon, Hydra, Nix, Kerberos, Styx, Dysnomia, Hi'iaka, Namaka (moons of dwarf planets), and moons/components of other trans-Neptunian object systems
The IAU formerly classified Pluto as a planet, Ceres as a minor planet/asteroid, and Eris as a minor planet/trans-Neptunian object.
© 2005-2012, 2015 by Wm. Robert Johnston.
Last modified 19 July 2015.
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