There are different types of planets and different ways to classify planets. One way is to arrange planets after their mass. Gas giant is called Jovian and is a massive planet with a thick atmosphere and a dense liquid core. In our solar system are Jupiter and Saturn Jovians. Neptunians are planets of the same order as Neptune and Uranus. A super-earth (also called Super-terrestrial) is a planet that is significantly larger than Earth but less than Neptune's about 10 times as large as Earth. A terrestrial planet is a planet of the same size as the Earth.
Planets are also arranged after composition: gas, water-gas, stone-water, stone-iron or iron. Or by temperature, warm, habitable or cold planets. Among extrasolar planets there is something called Hot Jupiter, it's a gas giant that orbit near its star and therefore has a very high surface temperature. These planets are the most common extrasolar planets, because they are relatively easy to detect.
There are seven different criteria that the researchers use to classify planets that can contain extraterrestrial life:
Earth Similarity Index (ESI) How similar to a planet is Earth on a scale between 0 to 1 where 1 resembles Earth most. ESI is based on the radius of the planet, density, air velocity and surface temperature.
Standard Primary Habitability (SPH) how suitable a planet is for vegetation on a scale of 0 to 1 where 1 is most likely to be possible for vegetation. SPH depends on the surface temperature of the planet
Habitable Zone Distance (HZD) distance from the center of the star's habitable zone so that -1 is in the outer zone and 1 is in the inner zone.
Habitable Zone Composition (HZC) The planet's composition values below -1 mean that the planet consists mostly of iron and values above 1 that the planet consists mostly of gas. Values close to 0 consist mostly of stone-water-iron.
Habitable Zone Atmosphere (HZA) is based on the possibility that the planet has a habitable atmosphere, the values below -1 mean that the planet lacks atmosphere and values above 1 that the planet has a very thick atmosphere and is probably a gas planet. Values close to 0 are not necessarily ideal for habitable atmosphere.
Planetary Class (pClass) is based on the planet's mass or temperature zone.
Habitable Class (hClass) Classifies planets by Temperature Hypopsychroplanets Cooler Than -50 ° C, psychroplanets Cold (-50-0 ° C), Mesoplanets Normal Temperature (0-50 ° C), Thermoplaneter Warm (50-100 ° C), Hyperthermoplanets warmer than 100 ° C.