The Mariner system, formerly known as the HD 28185 system and known simply as Mariner, is a gravitationally bound planetary system orbiting the G5V yellow dwarf Mariner, 128 lightyears from Sol in the constellation Eridanus. The Mariner system's largest objects are Mariner itself, the system's sole true star, and the six planets orbiting it, in order from Mariner: a terrestrial planet named Anchorage, a gas giant named Bluespring, Bluespring's L4 trojan terrestrial planet Bowsprit, a T5 brown dwarf named Tyrian, and two outer gas giants named Maelstrom and Sargasso. Bluespring, in particular, hosts two habitable Earthlike moons, Matariki and Tautoru.
These large bodies are accompanied by a large number of dwarf planets and asteroids concentrated primarily in the rocky Acroporan Belt, between Bluespring and Tyrian, and the icy Lophelian Belt, orbiting far past Sargasso, in a similar layout to Sol's Main Belt and Kuiper Belt.
Like the Sol system, Mariner is divided into an inner and an outer region by the Acroporan Belt, straddling the Mariner system's frost line and placing Anchorage, Bluespring, and Bowsprit in the inner system, while placing Tyrian, Maelstrom, and Sargasso in the outer system. With gas giants unable to form ahead of the frost line, it is believed that the massive gas giant Bluespring initially formed in the outer system before having its orbit destabilized by brown dwarf Tyrian, migrating to the inner system and capturing several smaller planets in the process.
Residents of the Mariner system have been recently christened Marinads, a formerly unofficial term now spreading as an adjective for Mariner as a whole.
History
First surveyed by science frigate SDCN Hellas Planitia in March 2116, the discovery of two fully habitable Earthlike moons orbiting the gas giant Bluespring — Matariki and Tautoru — generated immense interest in the then-HD 28185 system by the Final Frontier Project and the scientific community. A scientific outpost was immediately established near the two moons, with the system becoming a hotbed of FFP research and survey activity that revealed increasingly complex marine biospheres on both worlds, as well as barren and mineral-rich landmasses open for research and development.
Currently being developed by expeditionary carrier SDCN Telemachus and accompanying support vessels, the Mariner system now hosts a semi-permanent scientific population of 224, spread across orbiting stations as well as the moons Matariki and Tautoru.
The Mariner system likely formed some 4.6 billion years ago, with protoplanetary formation beginning soon after. Tyrian, a brown dwarf, is believed to have been on the verge of stellar ignition when Mariner began hydrogen fusion, creating a stellar wind that gradually destroyed the Mariner system's protoplanetary disk, along with Tyrian's accretion disk, preventing hydrogen ignition in the now-failed star. Nevertheless, Tyrian's incredible mass continued to exert incredible gravitational influence on the Mariner system's protoplanets, shattering such objects nearby and creating the rocky Acroporan Belt between the system's second and third planetary orbits.
Mariner
 | ||
| Mariner | ||
|---|---|---|
| System | Mariner | |
| Type | Star | |
| Astronomical Classification Index | M-G5V-1S | |
| Affiliation | Final Frontier Project | |
| Equatorial Radius | 0.953 R⊙ | |
| Mass | 0.941 M⊙ | |
Mariner's ACI code is M-G5V-1S.
Information
Mariner's radius is about 663,000 kilometres, or about 104 Earth radii, with a mass of about 1.882 × 1030 kilograms, or about 314,926 Earths, constituting 99.46% of the Mariner system's total mass. Mariner is thought to have formed in an extremely dense and relatively metallic nebula, due to the high relative total mass in the Mariner system and Mariner's high metallicity. In addition to Mariner itself, the system contains a super-Jupiter, Bluespring, and a massive T5 brown dwarf, Tyrian.
Compared to Sol, Mariner's outer system reaches are much larger and extend farther into the system. The Lophelian Belt, Mariner's icy outer system debris belt, extends to about 76 AU; Mariner's scattered disc objects have maximum apoapsides of around 140 AU and minimum periapsides of around 24 AU, and are both icy and rocky — thought to be caused by very high-mass objects (Tyrian and Maelstrom) in Mariner's outer system gravitationally scattering both Acroporan and Lophelian Belt objects into deep space.
Separate from the Acroporan and Lophelian Belts, Mariner hosts a small rocky debris belt of its own with no official name. This debris belt, informally dubbed 'the Breakwater' by Marinad researchers, is unusually rich in iron and other metals, and is thought to have originated from the breakup of either a metallic planet like Anchorage or an iron-rich planetary core left behind by a planetary vaporization event early in Mariner's history, during the star's hydrogen ignition.
Anchorage
 | ||
| Anchorage | ||
|---|---|---|
| System | Mariner | |
| Type | Terrestrial Planet | |
| Astronomical Classification Index | WOSLC-sE | |
| Equatorial Radius | 0.743 R🜨 | |
| Mass | 0.820 M🜨 | |
| Tidally Locked | Yes | |
| Orbital Radius | 0.294 AU | |
Anchorage, previously known as HD 28185 A1 and designated Mariner A1, is a near Venus-massed metallic terrestrial planet, tidally locked in orbit of Mariner at 0.29 AU. The rich inner system planet is notably tectonically active, with volcanic resurfacing seen in large, darker-coloured surface features like Antaba Mare, a massive basaltic plain covering much of Anchorage's Mariner-facing side, alongside older, heavily cratered surface regions like Wallenberg Regio.
Much of Anchorage's surface, especially on its light side, is coloured pale seafoam green due to the presence of a fine dust layer chiefly composed of callanite, an extrasolar mineral thought to be formed by extremely high-energy protoplanetary impacts.
Anchorage's ACI code is WOSLC-sE.
Information
Early surface exploration on Anchorage has uncovered massive, easily-accessible metal and mineral formations scattered throughout a nearly planet-spanning lava tube cave network. While portions of these lava tubes remain volcanically active, a majority have been tectonically cut off from areas of active volcanic activity, and as such, present feasible targets for underground colonization efforts, with easily sealable entranceways and directly accessible deposits of metals, minerals, and even rare earth metals left behind by ancient magma flows. Anchorage's poles, shielded from direct sunlight, also hold vast surface and subsurface deposits of usable water ice.
Identified, economically viable deposits in Anchorage's volcanic caves include iron, copper, gold, silver, platinum, molybdenum, tin, uranium, cobalt, selenium, manganese, yttrium, terbium, neodymium, praseodymium, lanthanum, scandium, and tungsten.
Bluespring
 | ||
| Bluespring | ||
|---|---|---|
| System | Mariner | |
| Type | Gas Giant (Sudarsky II) | |
| Astronomical Classification Index | THJOV-MJ | |
| Natural Satellites | Hōkūlei, Matariki, Tautoru, Sumu, Cymodoce (+173 others) | |
| Equatorial Radius | 12.310 R🜨 | |
| Mass | 6.124 M♃ | |
| Orbital Radius | 1.030 AU | |
Bluespring's ACI code is THJOV-MJ.
Information
Rings
Bluespring's vast ring system is mostly icy and, thanks to the gas giant's inner system orbit, is more visible than Saturn's, with a series of large ring gaps formed by the orbits of various shepherd moons and the orbital resonances of larger major moons. These gaps define Bluespring's ring segments — the intermixing white-tinted A, B, C, and D rings, the lavender-tinted E and F rings, the white-tinted G ring, the pale green-tinted H ring, the diffuse I ring, the tan-tinted J and K rings, and the dusty, mostly invisible M ring.
While most of Bluespring's rings remain unexplored, it is currently thought that the differing colourations of Bluespring's ring segments stem from the scattering of shattered moon or asteroid fragments containing certain coloured minerals.
Moons
Bluespring's enormous mass, alongside its position near the violent brown dwarf Tyrian, has allowed it to capture at least 178 moons, of which 20 have been officially named. These moons are accompanied by extensive co-orbital trojan clouds, including the L4 trojan planet Bowsprit, and include the four relatively massive, gravitationally rounded Astrapelagian moons.
These large, planet-massed major moons — Hōkūlei, Matariki, Tautoru, and Sumu — are believed to be former planets captured when Bluespring migrated closer to Mariner; the two Astrapelagians Matariki and Tautoru are fully habitable, and host developing marine biospheres.
While the four Astrapelagians are Bluespring's most famous moons, four roughly rounded, icy shepherd moons — Panopea, Nesaera, Maera, and Ephyra — help shape the gaps in Bluespring's icy ring system, and are each under investigation for the presence of a tidally-heated under-ice ocean, similar to Sol's Enceladean and Europan oceans. Twelve more moons are named, including the methane-shrouded major moon Cymodoce, while at least 170 others are confirmed to orbit Bluespring, with more discovered every month.
Matariki
 | ||
| Matariki | ||
|---|---|---|
| System | Mariner | |
| Type | Terrestrial Moon | |
| Astronomical Classification Index | TTMRN/H-sE | |
| Habitable | Yes | |
| Affiliation | Final Frontier Project | |
| Population | 90 | |
| Equatorial Radius | 0.618 R🜨 | |
| Gravity | 0.866g | |
| Mass | 0.331 M🜨 | |
| Orbital Radius | 11.949 R♃ | |
Matariki, previously known as HD 28185 A2f and designated Mariner A2f, is a habitable Earthlike moon of 0.331 Earth masses in orbit of the gas giant Bluespring. Matariki orbits Bluespring in an extremely stable 3ː2 orbital resonance with its fellow Earthlike moon Tautoru, completing three orbits for every two orbits Tautoru completes.
Matariki's ACI code is TTMRN/H-sE.
Habitability
Matariki is fully habitable, with a breathable nitrogen-oxygen atmosphere, comfortable temperature ranges, and extensive cloud systems. A small fraction of trace carbon dioxide in the atmosphere allows for Earthlike photosynthesis, while a relatively high inert atmospheric argon component signifies a lower internal proportion of Bluespring's tidal heating to radioactive decay heating; it is thought that Matariki, despite its less developed biosphere than Tautoru's, was already a relatively temperate world in its pre-Bluespring infancy, thanks to active potassium-argon decay in a very hot internal core. Polluting gases like those on Earth are almost nonexistent.
Compared to its resonant partner Tautoru, Matariki's rotation is calmer and more Earthlike, with a precisely 22 hour rotation period, dimly lit during the night by light reflecting off of Bluespring; when the gas giant blocks Matariki's view of its star, the moon experiences a roughly two hour 'blue night'. When the blue night coincides with Matariki's rotational night, the moon is entirely dark, with no moonlight like Earth to provide dim illumination.
Matariki's landmass is divided into vast, tectonically active continents, with familiar mountain ranges, deserts, lakes, and rivers to those found on Earth, bounded by a world ocean that covers 63.1% of the moon's surface. Tidally and tectonically active, even compared to the similarly tidally influenced Tautoru, much of Matariki's landmass is covered in relatively recent basaltic plains and lava formations; the moon's land area is growing by hundreds of acres per month, even as those same basaltic plans are rapidly eroded by powerful ocean tides. Underwater, Matariki's seabed is covered in volcanic seamount chains and tectonic rifts, making most of the moon's crust geologically young.
Matariki's islands and continents are devoid of life (excepting microscopic biofilm organisms on shorelines), while a developing marine biosphere occupies the moon's oceans. Compared to Earth's history, Matariki appears to be in a rough analogue to the Ediacaran Period, with soft-skinned multicellular organisms, including sessile animals, sponges, and lichen analogues, rapidly spreading across the moon's seabeds and coastal seas. Tidal pools, made deep and frequent by Bluespring's immense tidal forces on Matariki's oceans, play host to much of the moon's surface-facing life, where separate lineages of mobile plant life and small shelled fauna have emerged.
Settlement
Matariki's first and only settlement, Saltator, hosts the moon's FFP research population of 90, and was officially founded on 2 July 2116. Located at 54°20'36"N, 7°54'17"E, Saltator sits at the mouth of the Bluebell River, a meandering, silted river crossing much of the small continent of Zhongqiu before emptying into the sheltered Nansen Sea. Zhongqiu, one of Matariki's five continents (alongside Samhain, Ambarvalia, Kaamatan, and Nobanno), hosts climates ranging from windswept subtropical deserts to intricate fjord regions, with strong tidal whirlpools a common sight in Zhongqiu's northern fjords.
Saltator has direct access to the Nansen Sea, one of Matariki's most biologically active ocean regions and home to the recently classified Matariki-Nansen biota, with organisms distinguished from the world ocean's lineages through evolutionary adaptations to colder, calmer, and more mineral-sparse waters, such as thicker tissue walls, additional heat reservoirs, smoother shapes, and markedly aggressive feeding behaviour. Dotting the nearby coastlines are numerous large tidal pools sustaining isolated populations of their own, even more divergent from the biotas of Matariki's world ocean.
Matariki's near-perfect habitability, relative lack of biological development compared to its resonant partner Tautoru, and plentiful usable landmass have made it a prime target for FFP colonization and development efforts. While some development is marked for Saltator and the Nansen Sea area, the moon's first settlement is planned to remain research-focused, with major civilian, corporate, and military development first occurring in designated zones far from biologically active seabeds — namely on the windswept, rocky coasts of the northeastern Bruce Sea.
Tautoru
 | ||
| Tautoru | ||
|---|---|---|
| System | Mariner | |
| Type | Terrestrial Moon | |
| Astronomical Classification Index | TTMRN/H-sE | |
| Habitable | Yes | |
| Affiliation | Final Frontier Project | |
| Population | 110 | |
| Equatorial Radius | 0.603 R🜨 | |
| Gravity | 0.851g | |
| Mass | 0.309 M🜨 | |
| Orbital Radius | 15.656 R♃ | |
Tautoru's ACI code is TTMRN/H-sE.
Habitability
Tautoru is fully habitable, with a breathable nitrogen-oxygen atmosphere, comfortable temperature ranges and extensive cloud systems. Trace carbon dioxide allows for Earthlike photosynthesis, while a relatively low inert atmospheric argon component signifies a higher internal proportion of Bluespring's tidal heating to radioactive decay heating. Polluting gases like those on Earth are almost nonexistent.
The moon rotates quickly relative to its fellow moons and resonant partner Matariki, with a 6 hour, 22 minute rotation period, distorting the moon's clouds into ocean-crossing 'streak storms' carrying precipitation and lightning across the world; elsewhere, native life must contend with a year-long hurricane season and brisk moon-spanning winds.
Tautoru completes an orbit of Bluespring roughly every 72 hours, dimly lit during the night by light reflecting off of Bluespring; when the gas giant blocks Tautoru's view of its star, the moon experiences a roughly three hour 'blue night'. When the blue night coincides with Tautoru's rotational night, the moon becomes entirely dark, during which time much of Tautoru's shallow-water life becomes bioluminescent (glowing), presumably to counter this total light loss.
Tautoru is dotted with scattered volcanic archipelagos, separated by two vast and tidally active hemispheric oceans, the northern Rakataura Ocean and the southern Ui-te-Rangiora Ocean, covering 84.6% of the moon's surface. Between these archipelagos stretch vast seamount chains, adorned with multicoloured coral reef analogues creating intricate marine habitats and occasional atolls, with some reefs having created mazelike pseudo-mountains supporting vast microbial rock formations above the water. A majority of Tautoru's land is concentrated in the comparatively shallow and volcanically active Gold Belt, an area stretching from 20° north latitude to 20° south latitude, where silt, plankton populations, and microscopic nutrients carried towards the equator by hemispheric ocean currents give the warm tropical water a permanent turquoise colouration.
There is little macroscopic life atop Tautoru's many islands; the planet appears to be in an analogue to Earth's Cambrian Period, experiencing an explosion of solely oceanic biodiversity, including rough analogues to Earth trilobites, crustaceans, jellyfish, and even early fish analogues, along with unrecognizable spindle creatures and grappling predators. Large tidal pools, sustained by Bluespring's immense tidal forces, provide isolated habitats for unique coastal organisms superficially similar to Earth shellfish and algae, evolving separately from their world ocean-based counterparts.
Settlement
Tautoru's semi-permanent FFP research population of 110 resides in its first and only settlement, Symbioso, officially founded on 3 July 2116. Located at 9°18'38"S, 28°50'12"E, Symbioso is built on a deep, mountainous harbour, formed by an extinct volcanic caldera on the island of Sylphien that protects the settlement and nearby habitats from strong winds. Sylphien, the largest member of the Alyselian Islands, is home to Tautoru's highest known peak, the extinct volcano Mount Dunant, and is the third largest island in the tropical and relatively shallow Gold Belt, behind Gran Rossen and Tautoru's largest ice-free landmass, Unidad.
Symbioso is centrally placed to conduct biological and geological research, just twelve kilometres from a sizable coral reef formation and within walking distance of Sylphien's numerous tidal lakes, interspersed with strong coastal whirlpools. Through foot/wheel expeditions from Symbioso alone, a vast diversity of marine life, much of it appropriately mutualistic or commensal, has been discovered and catalogued inhabiting nearby reef formations, rock pools, isolated lakes, and deep volcanic trenches. From the settlement's newly constructed port, a flotilla of oceangoing science vessels has been assembled on-site to begin plying the Gold Belt for new habitats and species, while Symbioso's small air/spaceport, specially designed to minimize noise disruption to surrounding life, is planned to open in two weeks.
With much more plentiful and diverse life than its resonant partner Matariki, as well as less usable land area, Tautoru has seen much less prioritization for FFP colonization efforts, instead marked primarily for biological research, with small-scale colonization and development as a secondary focus. To this end, roughly half of the Gold Belt has been preemptively placed into a series of natural/scientific reserves by the Project, pending UN General Assembly approval.
Bowsprit
 | ||
| Bowsprit | ||
|---|---|---|
| System | Mariner | |
| Type | Terrestrial Trojan Planet | |
| Astronomical Classification Index | TNOCL-mE | |
| Equatorial Radius | 0.514 M🜨 | |
| Mass | 0.194 M🜨 | |
| Orbital Radius | 1.030 AU | |
Bowsprit, previously known as HD 28185 A3 and designated Mariner A3, is the first known trojan planet — a full-sized oceanic world of 0.194 Earth masses co-orbiting with Bluespring at the oceanic gas giant's L4 Lagrangian point, 60° ahead of the larger body, and kept stable by Bluespring's enormous mass relative to other gas giants.
Like Bluespring's Astrapelagian moons, Bowsprit is believed to be a planet captured by Bluespring's influence when the massive gas giant migrated inwards through the system, though it has kept its controversial planet classification thanks to its semi-independent and partially cleared orbital neighbourhood.
Bowsprit's ACI code is TNOCL-mE.
Information
Bowsprit is almost entirely covered in a deep liquid water ocean, with a few barren volcanic islands forming the planet's only visible landmasses. Despite its watery oceans, churning volcanoes, rain clouds, and Earthlike temperatures, Bowsprit's nitrogen-dominated atmosphere is devoid of oxygen and somewhat toxic, including a 1.44% atmospheric ammonia content, rendering the planet uninhabitable without proper suit protection.
Shallow water exploration efforts have yielded no evidence of oceanic life on Bowsprit, though deep sea submersible exploration to Bowsprit's extensive undersea vent system is underway in hopes of discovering abiotic or even more exotic life.
Tyrian
 | ||
| Tyrian | ||
|---|---|---|
| System | Mariner | |
| Type | Brown Dwarf | |
| Astronomical Classification Index | T-T5-MJ | |
| Equatorial Radius | 17.349 M🜨 | |
| Mass | 19.862 M♃ | |
| Orbital Radius | 12.130 AU | |
Tyrian, previously known as HD 28185 A4 and designated Mariner A4, is a T5 brown dwarf star of 19.86 Jupiter masses. A failed star, Tyrian is massive enough to fuse deuterium in its core, providing some illumination and heat, but cannot fuse hydrogen, having failed to achieve stellar ignition early in the Mariner system's formation. As a result, Tyrian glows in faintly magenta on its dark side, though this light is overpowered by Mariner's illumination on the brown dwarf's light side.
Tyrian's ACI code is T-T5-MJ.
Information
Tyrian's extreme mass is believed to have played a critical role in the evolution of the Mariner system. Unable to achieve stellar ignition after Mariner began fusing hydrogen, Tyrian nevertheless disrupted the orbits of various protoplanets in the outer reaches of the early Mariner system, and likely shattered a number of developing protoplanets into what is today's Acroporan Belt. Later on, Tyrian is also believed to have disturbed Bluespring's orbit in a random close pass with the gas giant, causing Bluespring to migrate into the inner system, capturing a number of smaller planets in its path and creating an inner boundary to the Acroporan Belt, while Tyrian defines the outer boundary.
A barely visible ring of mostly rocky debris closely orbits Tyrian, containing hundreds of small asteroids that are the brown dwarf's only natural satellites. Occasional gravitational disturbances from Tyrian can knock these objects out of orbit, causing them to quickly break up and impact Tyrian — an event the SDCN Telemachus witnessed during its system entry towards Bluespring on 16 May 2116 with the now-destroyed asteroid 2116 GV147, generating large amounts of chemical and atmospheric data for the study of Tyrian and other brown dwarfs.
Based on Tyrian's age, heating, and luminosity, the brown dwarf is believed to still be fusing deuterium, long after its deuterium supply should've been exhausted and leaving Tyrian to glow only from residual heat. While the causes for Tyrian's abnormal deuterium content are unknown, deuterium fuel scooping outposts have been proposed in low orbit of the brown dwarf.
Maelstrom
 | ||
| Maelstrom | ||
|---|---|---|
| System | Mariner | |
| Type | Gas Giant (Sudarsky II) | |
| Astronomical Classification Index | THJOV-SJ | |
| Natural Satellites | Hinnøya, Langøya, Austvagøya (+80 others) | |
| Equatorial Radius | 11.384 R🜨 | |
| Mass | 2.157 M♃ | |
| Orbital Radius | 23.971 AU | |
Maelstrom, previously known as HD 28185 A5 and designated Mariner A5, is a gas giant of 2.157 Jupiter masses. Covered in Sudarsky Class II water vapour cloud bands and heated by an extremely hot core, Maelstrom's planetary storms travel across the gas giant's surface at speeds exceeding 6,700 kilometres per hour, or roughly 1.87 kilometres per second.
Maelstrom's ACI code is THJOV-SJ.
Information
Maelstrom's defining visual features are its cloud bands — differentiated segments of water clouds and storms, floating through the gas giant's upper layers at Earthlike temperatures. These clouds, and Maelstrom's atmosphere as a whole, rotate extremely quickly relative to the rest of the planet, heated from below by Maelstrom's relatively hot core, and from above by Tyrian's interplanetary tidal forces and Mariner's sunlight. Though not tidally locked, Maelstrom's dark side, unlit by Mariner or by Tyrian, is much colder than its light side, creating a temperature differential that pushes air from one side to the other with windspeeds over 6,700 kilometres per hour.
Maelstrom's magnetosphere is the strongest in the Mariner system after Mariner itself's magnetosphere, with the gas giant's magnetotail often stretching beyond the orbit of Sargasso, disturbing Sargasso's magnetic fields when the two collide. Maelstrom's magnetic fields also create permanent auroras on the gas giant's poles, similar to Jupiter.
Moons
Of Maelstrom's 83 discovered moons, 10 are currently named, with the largest, Hinnøya, accounting for 96% of the total mass in Maelstrom's moon system. Other notable moons include Langøya, an icy moon partially covered in reddish organic tholins, and Austvagøya, an older, mostly rocky moon with extensive impact craters across its entire surface.
Hinnøya is a frozen rocky-icy moon of roughly 1.2 Luna masses, scarred by cryovolcanoes and surrounded by a dense water vapour atmosphere. Hinnøya's thick, watery atmosphere likely formed through frequently occurring cryovolcanic fumaroles on Hinnøya's surface, bringing warm water from Hinnøya's tidally heated interior or proposed subsurface ocean to the surface, with the expelled gases protected from Mariner's solar radiation pressure by Maelstrom's strong magnetosphere. Hinnøya is a prime candidate for the existence of a Europan/Enceladean subsurface ocean, thanks to the moon's high observed libration (orbital 'wobble') suggesting a complete detachment of Hinnøya's icy crust from its mostly silicate core.
Sargasso
 | ||
| Sargasso | ||
|---|---|---|
| System | Mariner | |
| Type | Gas Giant (Sudarsky I) | |
| Astronomical Classification Index | CHJOV-sJ | |
| Natural Satellites | Bermuda, Abaco, Caicos, Saint Kitts, Guadeloupe (+36 others) | |
| Equatorial Radius | 9.311 R♃ | |
| Mass | 0.381 M♃ | |
| Orbital Radius | 47.653 AU | |
Sargasso, previously known as HD 28185 A6 and designated Mariner A6, is a gas giant of 0.381 Jupiter masses, and is the outermost planet in the Mariner system. Coloured sandy tan by its Sudarsky Class I ammonia clouds, similar to Sol's Jupiter and Saturn, Sargasso was named for its resemblance to the sargassum seaweed found floating in Earth's oceans.
Sargasso's ACI code is CHJOV-sJ.
Information
Sargasso sits at the outer edge of the Mariner system, at 47.653 AU, with the icy Lophelian Belt — Mariner's equivalent to Sol's Kuiper Belt — beginning just beyond Sargasso's orbit, at around 62 AU. Receiving little of Mariner's sunlight, Sargasso's interior and moons are mostly internally or tidally heated, with none of the comfortable temperature ranges found nearby Bluespring or Maelstrom.
Moons
Sargasso hosts 41 moons, of which 11 are currently named. Five of these are Sargasso's gravitationally rounded, major moonsː Bermuda (the largest), Abaco (the most massive), Caicos, Saint Kitts, and Guadeloupe.
Abaco, Sargasso's innermost major moon, has been marked as a priority FFP exploration target; early observations have detected a circulation system of cryogenic liquid ammonia (NH3) on the moon, similar to Titan's methane cycle, including ammonia lakes, rivers, and weather systems, all shrouded in a dense nitrogen atmosphere.