Dwarf planet Ceres

Subject: Science and tech

Context:

Researchers have shed new light on the dwarf planet Ceres which now has the status of an “ocean world”, after scientistsanalysed data collected by NASA’s Dawn spacecraft.

Concept:

• There are officially five dwarf planets in our Solar System.
• The most famous is Pluto, downgraded from the status of a planet in 2006.
• The other four, in order of size, are Eris, Makemake, Haumea and Ceres. The sixth claimant for a dwarf planet is Hygiea, which so far has been taken to be an asteroid.
• Four criteria set by the International Astronomical Union (IAU) for a celestial body to be called a dwarf planet.
• The body orbits around the Sun, it is not a moon, has not cleared the neighborhood around its orbit (which means it is not the dominant body in its orbit around the Sun and this is what differentiates a planet from a dwarf planet) and has enough mass for its gravity to pull it into a roughly spherical shape.