Neptune (world)

From Traveller Wiki - Science-Fiction Adventure in the Far future
Jump to navigation Jump to search
Neptune/Sol (Solomani Rim 1827)
Classic Era (1115)
StarportS Error in Starport Decode
SizeG Error in Size Decode
AtmosphereG Error in Atmosphere Decode
Hydrographics Error in Hydrographics Decode
Population Error in Population Decode
Government Error in Government Decode
Law Error in Law Decode
Tech Level Error in Tech Decode
See also UWP
System Details
Primary G2 V
Planetoid Belts 1
Gas Giants 4

Neptune is a barren fluid hellworld with oceans of a liquid other than water such as ammonia, methane, or hydrocarbons, or other exotic liquids.

  • This world has no overt population, government, or law level.
  • Hellworlds often offer daily, and sometimes hourly, life-threatening situations to their inhabitants.
  • This world could be populated if anyone had an inclination to do so...
  • It is a member of the Third Imperium in the Sol Subsector of Solomani Rim Sector in the Domain of Sol.
  • This world-system hosts a Naval Base, usually associated with military starships, which may be located on or off-world.

Description / Astrography & Planetology[edit]

A small refueling station is located on Triton, its largest moon.

Monostellar System[edit]

Neptune Monostellar System
Star Name Hierarchy Category Mass (Sol) Temp (K) Luminosity (Sol)

G2 V

Primary Main Sequence 1 5100 - 5900 1
Unit Diameter Min Distance Hab Zone Jump Shadow M-Drive Limit
AU 0.0093 0.08294 0.8 - 1.3 0.93 9.3
Orbit #  *  * 3 3 7

System Data[edit]

The primary of the Terra system is Sol, an ordinary yellow main sequence star. It has a luminosity of 1 Sol, a mass of 1 Sol, and a diameter of 1.391 million km. Sol retains a family of four inner rocky worlds, a stony planetoid belt, and four outer gas giant worlds – the system is named for Terra, the mainworld.

  • Neptune is the outermost of the four outer gas giant worlds.
  • Neptune retains five major moons.


Neptune has a UWP classification of "SGG" and is categorised as an ice giant. It orbits Sol at a mean distance of 30.2 AU (778.5 million km) and has an orbital period of 164 years 299 days. It has a mean rotation period (a local day) of 16.1 standard hours, although the surface is not rigid and different regions of (and altitudes within) the world rotate at different rates. Neptune has a diameter of 49,244 km, a mean density of 1.64 g/cm³, and a surface gravity of 1.13 G. The world has a complex layered internal structure: its surface is defined as the point within the atmosphere where the mean pressure equals one bar (760.0 mm Hg), equivalent to the mean surface atmospheric pressure of Terra.


The core of the world has a diameter of approximately 11,000 km. It is primarily composed of small quantities of heavy elements such as nickel (Ni), iron (Fe), and substantial concentrations of silicates (SiO 4–). The core temperatures exceed 7,000°C and pressures exceed 7 megabars. The core is dynamic and active.


Above the core is a dense mantle with a diameter of approximately 135,000 km. It has a composition of water (H2O), methane CH4, and ammonia NH3 in the form of extremely compressed ices and slush.

  • The mantle is extremely viscous, though it is able to flow throughout its entire depth.

Ring System[edit]

Ring System (UWP YR00000-0)


Neptune's magnetic fields are caused by convective motions in the electrically conductive fluids of the mantle.


Major Satellites[edit]


Galatea (UWP YS00000-0) is the inner of the five major moons of Neptune and is classified as a worldlet. It orbits its parent world at a mean distance of 1.3 diameters (62,000 km), with an orbital period of 10.3 hours: it is tidally locked to Neptune. Galatea is an irregular spheroid with a long axis of 204 km, a density of 0.75 g/cm³ and a surface gravity of 0.0018 G. The atmosphere is rated as vacuum. The world has no surface hydrosphere. Mean surface temperature: -222°C.

  • Galatea is composed of a mixture of crystalline water-ice (H2O) and crystalline methane-ice (CH4), with small quantities of frozen ammonia (NH3), nitrogen (N2) and silicates. The crust is broadly similar in composition to the interior and contains trace amounts of tholins.

Larissa (UWP YS00000-0) is the second of the five major moons of Neptune and is classified as a worldlet.


Proteus (UWP YS00000-0) is the third of the five major moons of Neptune and is classified as a worldlet.


Triton (UWP H210169-E) is the fourth of the five major moons of Neptune and is classified as a worldlet.


Nereid (UWP YS00000-0) is the outer of the five major moons of Neptune and is classified as a worldlet.

Minor Satellites[edit]

No information yet available.

Native Lifeforms[edit]

No lifeforms are known to exist within Neptune.

History & Background (Dossier)[edit]

Neptune is a small gas giant, or "ice giant", located in the Terran system in Sol Subsector of the Solomani Rim.

Imperial High / Landed Nobility[edit]

Only the mainworld of a system possesses an officially appointed or landed Imperial Noble.

  • The landed nobles of this system are located at the mainworld on Terra.

World Starport[edit]


World Technology Level[edit]


World Government[edit]


World Military[edit]

No information yet available.

World Economy[edit]

No information yet available.

Trade Data[edit]

No information yet available.

World Demographics[edit]

No information yet available.

World Culture[edit]

No information yet available.

Historical Data[edit]

No information yet available.

World Timeline[edit]

No information yet available.

UWP Listing[edit]

No information yet available.

Image Repository[edit]

TravellerMap (T5SS):


62px-Information icon.svg.png This article is missing content for one or more detailed sections. Additional details are required to complete the article. You can help the Traveller Wiki by expanding it.