Planet



Planets are astronomical bodies which are gravitationally bound to the barycenter of a (star) system. They are usually surrounded by natural objects of smaller size (called moons), natural (asteroids, comets) and artificial space debris which can form visible planetary rings. If two planets surround each other and share the same barycenter, they are commonly called a binary planet.

Planets are the birthplaces of all known civilizations, provide most materials needed for survival, and are centers of research, culture, and development. Each planet is unique, from the massively terraformed ArcCorp to the aquatic haven of Cassel.

Origin
Planets, moons, and stars are formed in accreditation discs. Space debris, which is leftover of this process can be ejected extremely far away from the system's barycenter (i.e. Oort Cloud). Although rare, planets can also be ejected from a star system. These are designated "Rogue planets".

Classification
The ARK Starmap shows (as of February 2019) 21 different planet 'types', and lists 324 planets. Over the course of development, the types of some planets have changed. There is currently no indicator known on which basis these types for certain planets were chosen. The terms used by the Starmap for planets are not mutually exclusive, but for some reason, every planet has only one type. An example is Kampos: A super-earth and ocean planet, but it is only listed as a Super-Earth on the Starmap.

The ARK Starmap classification also includes Dwarf and protoplanets, even if they can have the size of an asteroid.

The listed types can refer to the mass, composition and unique characteristics of the planet. Some types are 'counterparts'. While sharing a common feature, they differ in other aspects. Gas Dwarfs and Gas Giants are gas planets while they are differentiated by mass. However, there is no type called Gas planet.

There are anomalies in the amount and cumulation of planets per system, i.e. Gurzil and Cathcart having no planets, while Kilian has 14 planets.

List of Planet Types According to the Starmap
In alphabetical order:

Types
The Starmap doesn't define what the planet 'types' exactly are. The following definitions are based on the assumption that the terms are self-descriptive and refer to their 'real-life' equivalents.

The presence of certain elements (gases constitute the atmosphere), the planet's density, an existing core (magnetosphere), and the surface temperature on a planet are significant factors for the development of specific features. A carbon planet, for example, would never have large amounts of water on its surface, because supplied oxygen would instantly react with the carbon.

Gas Planets
The moniker of "Gas Planet" leads most to believe these planets are filled mostly with soft clouds over a dense core. The reality is that for most of the planet's volume, the pressure is so high that matter is not in gaseous form. Other than solids in the core and the upper layers of the atmosphere, all matter is above the critical point, where there is no distinction between liquids and gases. In the outer regions of a Gas Planet's atmosphere, the title rings more true, with these more gaseous zones serving as vital manufacturing areas for larger vessels on some planets. Orison, located on Crusader is a prime example.
 * Gas Dwarf, a gas planet with a total radius between 1.7 and 3.9 Earth radii
 * Gas Giant, a gas planet with a radius higher than 3.9 Earth radii
 * Super Jupiter, its mass is larger than Jupiter and causes compacting and densification of the atmospheric gases. They constitute the borderline from gas planets to Brown Dwarfs.
 * Puffy planet (or Hot Jupiter), the counterpart of the Super Jupiter. They are lighter than Jupiter and have a larger radius.

Ice Planets
Defined by the abundance of heavier volatiles (elements with freezing points above about 100 K) such as methane, carbon dioxide, water, are predominant. These elements are frozen on the surface, while under the surface they could be liquid due to various reasons, i.e. tidal heating.
 * Ice giant: a gas planet with a mass higher than 10 Earth masses and a radius of 1,5 Earth radii and larger.
 * Ice planet: see definition above, it could refer to ice planets with up to 10 Earth masses.

Terrestrial Planets
Terrestrials are 'Earth-like' planets with an abundance of silicates, rocks, and metals.
 * Terrestrial Rocky planets have a rocky mantle and an iron core.
 * Desert planets are planets with a planet-wide desert "biome."
 * Carbon planets are primarily made of carbon and carbon minerals.
 * Iron planets are defined by having a mass mostly composed of a large percentage of iron. For example, Mercury's core contains up to 70% of its entire mass.
 * Coreless planets planets have a rocky mantle, but without a differentiated metal-based core
 * Planets with a fluid surface:
 * Ocean planets are refer to planets which are covered predominately by an ocean of water.
 * Lava planets are referring to planets which are covered by oceans of molten rock.
 * Smog planets seem to be terrestrial planets with a thick atmosphere consisting of smog (acidic, corrosive or poisonous air pollutants such as ammonia, hydrocarbon and sulfur dioxide).
 * Super-Earths have a mass higher than earth, but lower than 17 earth masses.
 * A Mesoplanet has a diameter between 473 Km (Ceres) and 4880 Km (Mercury). Science fiction writer Asimov coined the term.

Other Planets

 * Chthonian planets are the remnants of a gas planet losing its gaseous atmosphere. They are resemble terrestrial planets in many ways.
 * Rogue Planet is a term for a planet that doesn't orbit a nearby star. They are "free-floating" through space. The only known Rogue planet is Min I.
 * Synthworld is the only known Artificial planet. It is a planet which is being entirely constructed by the UEE.
 * Evaporating planet is a planetary body that is being evaporated due to its closeness to its star. The only documented case of an evaporating planet is Virtus I.
 * Dwarf planets are objects which are massive enough to maintain a hydrostatic equilibrium, but hasn't 'cleared his neighborhood' from other objects in the orbit. (However, the criteria of 'being a planet' used by ARK Starmap could be differing from today's standards. )
 * Protoplanets are made of planetesimals (very tiny chunks in a protoplanetary disc) and can reach the size of Dwarf Planets. Protoplanets can also be remnants of a system which was once formed, such as the Dwarf Planet Ceres.

Conclusion
2/3 of all ARK listed planets are terrestrial, about 1/4 can be considered gas planets.

Natural Reasons
The term disrupted planet refers to planets which were destroyed or 'disrupted' by another astronomical body. The following list gives a short overview of known disrupted and former planets (and natural satellites, if affected, too). Ellis XI and Odin I are listed by the ARK Starmap as asteroid clusters. Gainey is still listed as Odin Ia, while Odin I is dispersing into an asteroid field.

Hadesian Weapon
The Hadesians developed a 'planet-killer' weapon which they are presumed to have used against themselves after a civil war broke out. The only known usage was against Hades IV, with the use of this planetary super-weapon separating the planet into two distinct halves.

Travel
Travel and exploration on a planet can be done by most ships which are capable of landing on the surface or of atmospheric flight. Some ships, such as those with more aerodynamic surfaces (Hornet), will be more agile and efficient in atmospheric flight than others with fewer wings and control surfaces (Herald)

On the ground, terrestrial vehicles, like the Ursa Rover, will allow players to conduct trade, engage in combat, and complete missions, similar to most space careers.

Hypothetical, Undocumented and Fictionary Planets
Some lore documents (especially Short Stories) refer to content which seems to be fictionary within the SC Universe.
 * The Lost Generation takes place on Oso II. It is a 'real' planet but the plot seems to be partially fictional.
 * Sesen is the setting in Dateline:Sesen. There is no indication where this planet could lie, except the fact that Sesen and two other unnamed planets orbit the same star.
 * HL2610 and HH130782 only appear in a commercial for the Constellation Aquila.
 * The Krell System (with 9 planets) was promised as part of the game's crowdfunding campaign. It is home of the Kr'Thak, but is unknown to Humanity, since UEE and Kr'Thak never meet before. This system is more accurately "undiscovered."
 * There are several Vanduul systems which are "military classified" and don't show any planets.
 * The Xi'an Empire could be exceptionally large since this species has been traveling to the stars long before 387 BC.
 * RyiXy’an (Hyoton III) was the homeworld of the Xi'an. His position is unknown.
 * The Banu planet Queeg is only mentioned in Cassandra's Tears: A Cal Mason Adventure.

Notable Planets

 * Terra : Cultural capital of the UEE and his counterpart: Earth
 * Synthworld: An entirely artificial planet, its progress towards completion has been slow but not abandoned.
 * Tomb: Vanduul-patrolled pasture ground planet covered in wrecks and salvage.
 * Min: A Rogue planet and center of the Min System.
 * QuarterDeck: UEE's prison planet.
 * Jalan: Previous homeworld of the Tevarin that has been terraformed and renamed.
 * Armitage, Crion, Virgil I: Once settled by humans, now a pasture ground of the Vanduul
 * Cole, Ashana, Gonn, Uriel: Planets settled by Outlaws and pirate packs
 * Mya: Home of the 'Outsiders'.