Pluto & Dwarf Planet Facts
Artists impression of the distant dwarf planet Eris and its moon Dysnomia
- The dwarf planets of our solar system are Ceres, Pluto, Eris, Makemake and Haumea.
- Ceres is in the asteroid belt, a region of rocky bodies between the orbits of Mars and Jupiter.
- Pluto, Eris, Makemake and Haumea orbit in the Kuiper Belt, a region of icy bodies 2.8 billion miles (4.5 billion km) from the sun. These objects are also classified as Plutoids.
- The largest dwarf planet is Pluto, it has a diameter around half that of the planet Mercury
- Eris is the second largest of the dwarf planets, it is around two thirds the size of our moon.
- At its furthest point Eris orbits the sun at a distance of 14 billion km and takes 557 years to make one orbit.
- The smallest dwarf planet Ceres was previously classified as an asteroid, it is around a quarter of the size of our moon.
- A cluster of bright spots on the surface of Ceres are believed to be light reflecting of deposits of ice.
- The dwarf planet Pluto has a very thin atmosphere consisting of nitrogen, methane and carbon dioxide.
- The largest moon of Pluto, Charon, is half the size of the former planet.
- Eris, Makemake and Haumea were discovered between 2003-2005.
What is a Dwarf Planet?
The dwarf planet Makemake orbits in the Kuiper Belt
Dwarf Planet Pluto
Artists impression of Pluto's frozen surface
The largest moon of Pluto, Charon.
Missions to Dwarf Planets
DawnLaunch: September 2007
Arrival: March 2015
Summary: Dawn completed the first part of its mission which was to study the large asteroid Vesta. It successfully entered into orbit around the asteroid in July 2011 before leaving in September 2012. In March 2015 the craft successfully entered into orbit around Ceres and began analyzing and imaging the dwarf planet's surface in late April. Dawn has been the first craft to successfully enter into orbit around two separate bodies, this is thanks to the crafts ion propulsion engine (pictured left), which is more fuel efficient than a conventional chemical rocket allowing it to make more maneuvers and run for longer. The goal of the mission is to characterize the early solar system and determine how size and the presence of water influenced the evolution of planets.
New HorizonsLaunch: January 2006
Arrival: July 2015
Summary: NASA launched New Horizons in January 2006 thus taking advantage of a once in a life time chance to use Jupiter as a gravity assist towards the Pluto system. It arrived at Pluto in July 2015 thus becoming the first spacecraft ever to visit the planet. The craft made a very close flyby of the dwarf planet at a distance of just under 8,000 miles (12,500 km). During the approach and flyby striking images and data were also gathered of Charon and the other moon's of Pluto. Due to the huge distances involved and the enormous amount of data gathered by New Horizons it will take almost a year and a half for it to transmit all the data it acquired during the flyby.
Pluto StatisticsDiameter: 1,473 miles (2,370 km)
Average Distance from Sun: 3.6 billion miles (5.9 billion km)
Orbital Period: 248 years
Rotation Period: 6.39 days
Maximum Surface Temperatures: -218C (-360F)
Minimum Surface Temperatures: -240C (-400F)
Mass: 0.22% Earth's Mass
Density: 40% Earth's Density
Atmosphere: Nitrogen, methane, carbon dioxide. Discovery Date: 1930
Ceres StatisticsDiameter: 590 miles (950 km)
Average Distance from Sun: 257 million miles (414 million km)
Orbital Period: 4.6 years
Rotation Period: 9 hours
Maximum Surface Temperatures: -37C (-35F)
Minimum Surface Temperatures: -143C (-225F)
Mass: 0.015% Earth's Mass
Density: 38% Earth's Density
Atmosphere: Very small amounts of water vapor. Discovery Date: 1801
Eris StatisticsDiameter: 1,442 miles (2,320 km)
Average Distance from Sun: 6.3 billion miles (10.2 billion km)
Orbital Period: 557 years
Rotation Period: 26 hours
Maximum Surface Temperatures: -217C (-359F)
Minimum Surface Temperatures: -240C (-405F)
Mass: 0.28% Earth's Mass
Density: 46% Earth's Density
Atmosphere: Tenuous atmosphere consisting of methane. Discovery Date: 2005