Celestial body

Version

This article has been verified for the current PC version (2.6) of the game.

Celestial body

Classification

Colonization

Terraforming

Planetary features

Planet modifiers

A celestial body is a star, planet, moon or asteroid present in a star system. Celestial bodies may have resources which can be harvested by orbital stations. Each start system can have between 2 and 15 celestial bodies.

When any owned ship enters a system or passes within its sensor range, any habitable planets in the system will be revealed along with their world type. To see further details about the celestial bodies in a system, it is necessary to survey them with a science ship. This will reveal all of the orbital resources associated with each planet or asteroid. For habitable worlds this will also reveal more detailed world information including: size, available districts, blockers (if any), special features, and the habitability percentage for each species in the player's empire. Additionally, surveying worlds has a chance to reveal anomalies.

Habitable worlds

A habitable world is any celestial body that can harbor advanced organic life. These are the only worlds that can be colonized and terraformed, besides some notable exceptions. Their suitability ranges in accordance to a given species' homeworld, which affects the rate of population growth.

A planet's habitability (and subsequent future terraforming costs) is determined by its climate system. The nine habitable worlds are divided equally into three climate categories: dry, frozen and wet.

	Type	Climate	Description
	Arid	Dry	Dry, rocky world with a nitrogen-oxygen atmosphere. The dust-covered terrain consists largely of mesas and canyons. Forests can be found in the more temperate polar regions, but vegetation is otherwise scarce.
	Desert	Dry	Dry, rocky world with a nitrogen-oxygen atmosphere. Precipitation and major bodies of surface water are relatively rare. Significant temperature variations between day and night cycles. Vegetation is scarce, but even moderate precipitation can make the desert bloom.
	Savanna	Dry	Rocky world dominated by dry, arid plains covered by a nitrogen-oxygen atmosphere. The small hydrosphere allows for brief wet seasons, but aside from a few ubiquitous grasses vegetation is largely concentrated around shallow oases.
	Alpine	Frozen	Mountainous world with a nitrogen-oxygen atmosphere. Snow covers the mountaintops and frozen-over lakes dot the valleys. While the planet experiences the minimal seasonal variations, the still-liquid water beneath the frozen surface of the lakes is enough to sustain some hardy vegetation.
	Arctic	Frozen	Frigid, rocky world with a nitrogen-oxygen atmosphere. The poles are big, and significant water deposits can be found permanently frozen as glacial ice. However, the planet experiences seasonal variations and the equatorial band is covered by vegetation.
	Tundra	Frozen	Cold and rocky world with a nitrogen-oxygen atmosphere. Permafrost covers most of the surface except for the more temperate equatorial regions. A stable biosphere exists but vegetation is mostly limited to mosses and lichens.
	Continental	Wet	Rocky world with a nitrogen-oxygen atmosphere. Active and stable hydrosphere. Great landmasses are separated by oceans, with large climate variations depending on latitude and precipitation.
	Ocean	Wet	Rocky world with a nitrogen-oxygen atmosphere and a significant hydrosphere. Oceans cover more than 90% of the surface, with scattered islands making up the remaining percentage.
	Tropical	Wet	Humid, rocky world with a thick nitrogen-oxygen atmosphere. Seasons with significant precipitation are interchanged with drier periods. Most landmasses are covered in dense vegetation.

Special habitable planets

Special habitable worlds can only be spawned in certain systems but any empire that meets the requirements can terraform a regular habitable world into a special one. All of them have either very high or very low habitability.

	Type	Source origin	Terraforming requirements	Pop effects	Notes
	Gaia	Life-Seeded Elder Race	World Shaper ascension perk Nu-Baol Life-Seeding decision Cannot be terraformed again	100% Habitability +10% Biological Pop Happiness +10% Lithoid Pop Happiness +10% Resources from Jobs	Gaia Worlds tend to have positive modifiers and no negative ones. Most DLCs add at least one system with a Gaia world but a few can be found in all versions: A system called Wenkwart will always spawn in the galaxy. It contains size 19 Gaia world called Wankward Artem with a unique planet modifier. A size 25 Gaia world called Zannam will occasionally spawn in a galaxy. It is defended by the Guardians of Zanaam. Four Gaia worlds with special names - Prophets Retreat, Walled Garden, Emerald Mausoleum, Pristine Jewel - border the systems of the Holy Guardians. They have the Holy World modifier and colonizing them will incur their ire. Destroying them will even awaken the Fallen Empire.
	Tomb	Post-Apocalyptic	Armageddon bombardment Javorian Pox bombardment	0% Habitability	Tomb Worlds are habitable but feature the poorest base habitability and very few Planetary Features. Also, a species cannot be gene-modified to suit a Tomb World except through the Horizon Signal event chain. Pre-FTL civilizations in the Atomic or Early Space Age have a small chance of starting a nuclear war and turning the planet into a Tomb World. Empires with the Determined Exterminator civic start on a Tomb World if they don't have the Resource Consolidation Origin. Colonizing a Tomb World will displease the Traditionalist faction, unless the empire has the Post-Apocalyptic Origin. Each Tomb World has a high chance of triggering one of 8 unique events 2 or 3 years after the planet is colonized.
	Ecumenopolis	Elder Race	Arcology Project decision Restore Ecumenopolis decision Cannot be terraformed again	100% Habitability +20% Resources from Jobs +50% Pop Growth speed	The only pre-existing ecumenopolis is the homeworld of the Keepers of Knowledge Fallen Empire All normal planetary features are removed. Planetary Prospecting decision disabled. These city planets have their own set of districts that focus on providing massive amounts of Housing and refining basic resources. The city lights of an Ecumenopolis World are determined by the ship appearance of the terraforming empire. Empires that are Gestalt Consciousnesses or have the Agrarian Idyll civic cannot take the ascension perk but can still use conquered Ecumenopolis Worlds.
	Relic	Remnants		80% Habitability	Relic Worlds can be found in the First League precursors home system or in various systems added in the Ancient Relics DLC. Relic Worlds contain unique Planetary Features that grant bonuses to Research output. However most of the surface is covered by Blockers that are expensive to remove. Relic Worlds have the aforementioned Restore Ecumenopolis decision available. It terraforms the planet into an Ecumenopolis but loses its Planetary Features. If an Archeological site was present and not fully excavated it will be lost.
	Hive		Hive Worlds ascension perk	100% Habitability if Hive-Minded 0% Habitability if not Hive-Minded +10% Resources from Jobs	All normal planetary features are removed. Number of resource districts no longer limited by features. Planetary Prospecting decision disabled. Hive District effects are doubled on Hive Worlds.
	Machine	Resource Consolidation	Machine Worlds ascension perk	100% Habitability if robot 70% Habitability if Cybernetic 0% Habitability if neither +10% Resources from Jobs	All normal planetary features are removed. Number of resource districts no longer limited by features. Planetary Prospecting decision disabled. Cannot support Agriculture Districts. The following planetary modifiers will also be removed: Atmospheric Aphrodisiac, Atmospheric Hallucinogen, Bleak, Hazardous Weather, Hostile Fauna, Irradiated, Lush, Natural Beauty, and Wild Storms. If when terraformed the planet contains biological Pops that don't have the Cybernetic trait they are killed and the machine world gains an Organic Slurry planetary feature.

Uninhabitable celestial bodies

All non-star celestial bodies that cannot harbor advanced organic life are classified as uninhabitable. These worlds can't be colonized or terraformed, but some can have deposits of common or strategic resources.

	Type	Potential Common Resources	Potential Strategic Resources	Description
	Asteroid	Minerals	Volatile Motes	A larger asteroid or planetoid standing out in the dense cluster of smaller bodies.
	Ice Asteroid	Minerals	Rare Crystals	A larger asteroid or planetoid composed primarily of frozen H2O.
	Crystalline Asteroid	Minerals	Rare Crystals	A large asteroid covered in some kind of crystalline outcroppings. May contain Asteroid Hives
	Barren World	Minerals Physics Research		Barren and rocky world with a thin or non-existent atmosphere. The surface is covered in meteor impact craters and completely devoid of life.
	Barren World (Cold)	Minerals Physics Research		Barren and rocky world with a thin or non-existent atmosphere. The surface is covered in meteor impact craters and completely devoid of life.
	Broken			World devastated by some cataclysmic event. Whatever properties it may once have had are no longer discernible.
	Frozen World	Minerals Engineering Research	Rare Crystals	Rocky world covered in a thick layer of permanently frozen ice. Low temperatures and a very thin atmosphere precludes the existence of life on the surface.
	Gas Giant	Energy Engineering Research	Exotic Gases Zro	Gaseous planet with an atmosphere primarily composed of hydrogen and helium surrounding a dense core.
	Molten World	Energy Minerals Engineering Research	Volatile Motes	Rocky world that is scorching hot. The atmosphere is thin or non-existent, and lava from the interior flows freely due to constant volcanic eruptions. This type of planet cannot sustain organic life.
	Toxic World	Minerals Society Research	Exotic Gases Zro	A rocky planet with a thick atmosphere that is lethal to all known higher forms of life.

Special uninhabitable planets

Special uninhabitable planets can only be created in unique systems or as a result of events.

	Type	Notes	Description
	AI	These planets are created by the Contingency. They are similar in appearance to Machine worlds, but are not habitable at all. Successful bombardment turns the planet into a broken world.	Rocky world covered with artificial structures. The thin atmosphere consists mostly of industrial pollutants. There are strong energy emissions coming from across the entire surface, but no organic life signs.
	Cracked	Created by the hatching of the Voidspawn, destroying the existing colony. Has a deposit of 20 Society.	The cracked shards of an enormous planet-sized egg.
	Infested	Created when habitable worlds are infested by the Prethoryn Swarm. Successful bombardment turns the planet into a barren world that can be terraformed.	The surface of this world is covered by some kind of biological contaminant.
	Nanite	Found in the L-Cluster, with half of the outcomes giving them the Terraforming Candidate modifier once the nanite factory is destroyed.	A chaotic and inhospitable world, disfigured according to some mad design.
	Shattered	All worlds will have a deposit of 4-16 Minerals.	The charred, broken remnants of what was once a planet. A massive energy surge has detonated this world's core, leaving only slabs of rock.
	Shielded	Found through exploration, where the shield can be brought down through a special project with different possible outcomes. They can also be created using the Global Pacifier Colossus weapon but these worlds cannot then be un-shielded.	This entire world is encased in some kind of impenetrable energy barrier. It blocks all scans of the surface.
	Shrouded	Created by the End of the Cycle or when the Eater of Worlds is ravenous. Cannot be recovered. A few shrouded world can be found in some special systems.	Our sensors are unable to penetrate the thick fog surrounding the planet. Ships that enter it do not return.

Habitable Megastructures

Habitable Megastructures are entirely artificial and can be constructed after researching the required technology. They feature the same habitability for every species, have unique Districts and have no colonization cost.

Type	Size	Required technology	Notes	Description
Habitat	6	Orbital Habitats	Has 3 types of Districts, with a fourth one being available if build over a planet with a resource deposit Colonization is 3 times as fast as a planet	An artificial deep-space arcology offering planet-like, if decidedly urban, living conditions. Hydroponics and advanced filtering technologies make it near-self-sustaining, and station-borne facilities can mine the station's host planet for raw materials.
Ring World	5	Ring World	Ring Worlds have +20 free Housing Intact Ring Worlds are found only in the the Sanctuary system and the Ancient Caretakers home system Can be repaired from broken segments with the Mega-Engineering technology Can be built in uninhabited systems Segments destroyed by a crisis or World Cracker cannot be repaired	An immense band encircling the system's sun. Built to allow for numerous artificial habitation zones along its inner span, freed from the restrictions and mundanity of planet-bound, spherical existence.

Stars

A star is a celestial body that composes the center of a star system and influences the generation of the solar system. They are classified based on their spectral characteristics. Less common stars also have a negative effect on all ships in the system, making certain tactics less effective in battle.

Most systems have only one star but a few have two or three stars, either orbiting each other with the planets around them or far enough from each other that a few planets orbit each star.

	Type	Potential Resources	Description
	Class B	Energy Physics	The large class B main-sequence stars are very bright and blue. Although somewhat rare, the luminosity of these stars make them among the most visible to the naked eye.
	Class A	Energy Physics	These relatively young white or bluish-white main-sequence stars are typically among the most visible to the naked eye. They are large and rotate very quickly, but will eventually evolve into slower and cooler red giants.
	Class F	Energy Physics	F-type stars are fairly large and often referred to as yellow-white dwarves. Although they often emit significant amounts of UV radiation, their wide habitable zones have a good chance of supporting life-bearing worlds.
	Class G	Energy Physics	Often referred to as yellow dwarves, G-type stars actually range in color from white to slightly yellow. Main-sequence stars fuse hydrogen for roughly 10 billion years before they expand and become red giants. Although their lifespans are shorter than K-type stars, worlds inside the habitable zone of a G star often enjoy optimal conditions for the development of life.
	Class K	Energy Physics	These main-sequence stars, sometimes referred to as orange dwarves, are a fairly common sight. They are stable on the main-sequence for up to 30 billion years, meaning that worlds orbiting a K-type star have a longer than average window to evolve life.
	Class M	Energy Physics	The most common stars in the universe, often referred to as red dwarves. Their low luminosity means they are difficult to observe with the naked eye from afar. Although they typically have an extremely long lifespan, red dwarves emit almost no UV light resulting in unfavorable conditions for most forms of life.
	Class M Red Giant	Energy Physics	With a large radius and comparatively low surface temperature, red giants are stars of moderate mass in a late stage of stellar evolution. Their expanded stellar atmosphere and high luminosity make for distant habitable zone orbits.
	Class T Brown Dwarf	Energy Physics	Brown dwarfs are substellar objects that lack the mass to sustain hydrogen fusion. Roughly the size of large gas giants, they have a much greater density. Their low luminosity and comparatively small heat generation means that planets orbiting them are unlikely to support life.
	Pulsar	Engineering Physics	Pulsars are highly magnetized neutron stars that emit beams of electromagnetic radiation. As the star rotates, the radiation beam is only visible when it is pointing directly at the observer. This results in a very precise interval of pulses, which sometimes is so exact that it can be used to measure the passage of time with extreme accuracy. The radiation emitted by pulsars interferes with deflector technology, rendering ship and station shields inoperable. +100% Shield Nullification
	Black Hole	Engineering Physics Dark Matter	Typically formed as a result of the collapse of a very massive star at the end of its life cycle, black holes have extremely strong gravity fields that prevent anything - including light - from escaping once the event horizon has been crossed. The gravitational waves emitted by black holes interfere with FTL drives, making it harder for ships to escape from combat. +50% Disengagement Chance Reduction +50% Emergency FTL Jump Cooldown Allows starbases to construct the Black Hole Observatory building.
	Neutron Star	Engineering Physics	These incredibly dense stellar remnants are sometimes created when a massive star suffers a rapid collapse and explodes in a supernova. Although their diameter is typically as little as ten kilometers, their mass is many times greater than an average G-type star. The gravitational waves and radiation emitted by Neutron Stars must be carefully navigated around, slowing the sublight speed of ships. +50% Sublight Speed Reduction

References

Game concepts