9 World Chronicles

Types of Planets.

Chthonian Planets. 

Chthonian planets are celestial objects revolving close to a star. which were originally gas giants, but had their helium and hydrogen atmospheres stripped away by high temperatures emanating from their respective nearby stars. leaving behind a metallic and rocky core. There are no chthonian planets in our solar system, but there are several such planets that have been observed including Kepler-57b and Kepler-52b.

In Greek, Etruscan, Hittite and Dogon mythology these planets were linked an ancient type of demon noted for high intelligence and lost knowledge. 

The Carbon Planet. 

A carbon planet is believed to have a higher concentration of carbon than oxygen in its composition. Such planets have cores made of iron or steel, characteristic to terrestrial planets. The surface of these planets is believed to be covered by liquid or frozen hydrocarbons with a layer of graphite or diamonds several miles thick beneath the surface.

The Gas Dwarf.

A gas dwarf is a celestial body with a solid core but covered by a thick atmosphere made up of helium, hydrogen and other volatile gases. The gas dwarf is similar in composition to the gas giant planets and only differs in size. One example of a gas dwarf is Kepler-138d which is an extrasolar planet.

The Gas Giant. 

Gas giants are planets which are mainly made up of helium and hydrogen and other volatile compounds. These planets, which exist in immense sizes, are some of the largest known planets. Our solar system has two planets that are classified as gas giants, and these are Saturn and Jupiter. These planets are believed to have a molten rocky core. However, the properties of the compounds that exist in the cores of these gas giants are poorly understood due to the great temperatures and pressure.