The Saturnia System: One Last Time For the Road

Overview

Embedded deep in the Euplokamis Spine, Saturnia lies as a drifting star on the outskirts of the old, dim Polycystine Cluster, which is itself well on its way out. With a peak mass of only around 2,000 times the Sun’s and a current one of just under 400 Suns, this was never an especially massive and stable cluster. Its current crossing of the Euplokamis Spine only exacerbates its moribund condition; all the remaining stars but a small contingent of white dwarfs at its core are expected to fall apart within the next 20 million years. For Saturnia, which has never interacted significantly with its siblings, this is not all that large of a change.

Saturnia is a relatively young system, but of an age permissive to the evolution of life. Despite this, none of its six habitable worlds have any native life, possibly because their early oxygenation through photolysis prevented the formation of reducing hydrothermal environments that early lifeforms needed to form.

Nevertheless, modern Saturnia teems with life, having been settled by the echinodermatous inhabitants of Geometra in the last 200 years. They have wasted little time in making full use of the then-empty system, having covered the habitable worlds in biological hard drives and turned the Neptunian world Cerradopatus into the galaxy’s largest artificial neural network.

The First and Only Sun: Hexancistra, the Venerable Youth

Hexancistra is an intermediate white F5 star of relative youth at only around a billion years old. Due to this youth and its correspondingly rapid rotation, the star is quite active, frequently shooting off massive flares and coronal mass ejections (though not enough to qualify it as a flare star). The photolysis of planetary atmospheres caused by this periodic radiation blasting is thought to be the reason why its terrestrial worlds have oxygenated atmospheres despite having no (native) life.

The system contains an array of relatively small planets scattered throughout its habitable zone, bookended by a couple larger worlds. It is evident that the normal process of planet formation was terminated unusually early, as the total mass of the planetary system is abnormally low. Perhaps a nearby supernova cleared most of the protoplanetary disk or photoevaporation from massive stars in the ancestral Polycystine Cluster did the job, but in either case this half-baked system has been cast off into the void in its incomplete state. Until recently there were large belts of asteroids interior and exterior to the planets, but these have been deconstructed by the system’s inhabitants.

Inner Worlds

We All Fall Down

The molten, evaporating surface of Dardanus can hardly be distinguished from its glowing silicate cloud cover in this nightside shot.

Lunar Horizon Glow

Levitated dust particulates charged by intense radiation emissions from Hexancistra combine with Galthea’s practically nonexistent atmosphere to cast a barely-noticeable cloak over its crescent.

Transit Event

Carbonaceous asteroid Ulloaia crosses the tan, dried-out disk of Porcellana. Though once promising, this Venus-like planet has followed in the way of so many other now-dead worlds.

The Inner Worlds of Hexancistra represent a small set of terrestrial planets well interior to the habitable zone. With abundant access to sunlight all three have been massively reshaped by the force of insolation; Dardanus has been fried to a crisp, Galathea has been flayed of its atmosphere, and Porcellana has been baked dry. Unlike the other planets of the system, which are volatile-rich, all the Inner Worlds are nearly bone-dry. Unlike in other systems where rocky planets never had water to begin with, it is thought that these once began like their outer siblings before losing their supplies of the vital fluid to the ravages of their sun.

Members of the Inner Worlds

Graze the cloud tops of a world from hell. Though this super-Earth would be attractive real estate if it were placed in the habitable zone, it grows nothing but flame at its present orbit just 5% of the distance between the Earth and Sun. As the molten surface circulates in torrential downpours of lava, one wonders how even an indifferent universe could let such chaos reign unopposed.
Dardanus thinks your concerns about global warming are cute.
Swing by a small, barren world. This Mercury-like planet’s high surface temperatures and low gravity have allowed the solar winds to strip away any semblance of atmosphere. But storms still rage on this little world; static-driven currents levitate huge dust fronts kilometers into the nonexistent air.
Galathea bakes under the ionizing light of a forever-youthful sun.
Regard a world of wasted potential. This Venus-like terrestrial planet once possessed surface oceans, but powerful ionizing radiation emitted by Hexancistra caused its water to escape, leaving only vast pans of evaporite minerals. Soon even these will disappear, annihilated by resurfacing events.
Porcellana does not respond, dead as a doornail.

Intermediate Resonant Series

A World Gone Beautiful

Cerradopatus and Tertipatus hang in the void as a pair of narrow crescents painted with wonderful viridian hues. Such beauty is however underscored by its artificiality; Cerradopatus’s current state is just a few centuries old.

Glancing Blow

The rings of Actias cut a gleaming razor’s edge through its crescent from the view of its moon Argema. Little trace remains of the cataclysm that created them.

Valleis Marineris

A deep, seasonally arid river valley cuts through tall basalt plateaus on the thus-far pristine continental surface of Gonimbrasia. The seas now teem with artificial life, but these lands are still barren with the exception of the occasional spot of lichen.

Fraternal Twins

The crisp, frigid face of Saturnia contrasts greatly with the steaming, cloud-shrouded seas of Antheraea and the barren wastes of Syntherata. Though born from the same fire, these three worlds have followed drastically different paths.

Polar Desert

A frigid seashore on Samia’s northern continent reflects the deep aquamarine of its thin sky. Though the air is cold, no snow falls - the cold suppresses rain, leaving the land bone-dry.

Shell-Shock

The halogenated, extremely toxic atmosphere of Lonomia transforms the white light of Hexancistra into a sickly chlorotic green.

One Among Untold Billions

The rings of Attacus take on their characteristic shine as the fine-grain rock dust lights up under the glow of Hexancistra. Thousands of larger particles, a minuscule subset of the billions that populate the rings, drift into and out of the view.

The planets of the Intermediate Resonant Series are the greatest sign of Saturnia’s arrested development. Save for the warm Neptunian world Cerradopatus, all the planets of this region are significantly less massive than Earth and only barely able to retain their present nitrogen-oxygen atmospheres. Most are large enough to sustain geologic activity indefinitely, but their small size still suggests that their ancestors did not have enough time to consolidate into a smaller number of larger worlds before the protoplanetary disk dissipated. This would have been fortunate for any organisms that might have inhabited Saturnia were it left alone, for these small worlds form a veritable constellation of strange environs perfect for a burst of evolutionary innovation.

Members of the Intermediate Resonant Series

Journey to a world artificial, changed overnight to be utterly unrecognizable. A few centuries ago, this warm Neptune and its acidic, lacustrine moon were unremarkable. When the system’s alien masters arrived, though, they saw fit to commission a wondrous ecosystem to fit these worlds undeserving.
Cerradopatus owes its natural beauty to a wholly unnatural benefactor.
Visit a world devouring its own children. The dense, optically-thick rings of this young terrestrial world could only have formed from the annihilation of a moon of considerable size. Dozens of large craters and an ongoing rain of meteoric dust stand testament to this ancient cataclysm.
Fly past a deceptive, hungering world. This small terrestrial planet might seem inviting with its open, shallow seas, clement conditions and generally unassuming weather, but do not be fooled. An experiment gone rogue has covered the surface of this world in a planet-wide eusocial superorganism that rarely hesitates to devour unwary foreigners.
Gonimbrasia hungers, biding its time to devour the universe.
Swing past the complex dance traced by a triplet of rocky worlds. This binary pair of small terrestrial planets do not intrinsically differ that much but exist on an alternating cycle of hothouse and icehouse conditions that permanently casts them in opposition; one white with tropical clouds, one clear blue with arctic seas.
Saturnia and Antheraea barely notice the intrusion of outside forces.
Stand in the presence of a cold beauty. This small world with its thin atmosphere retains little heat, carpeting its higher latitudes with thick sheets of glaciers. Its lands are barren but the cold, highly-oxygenated oceans play host to a wondrous artificial ecosystem.
Samia remains untouched by rapacious commodification.
Traipse through a harsh and freezing hell. Though not physically divergent from its brethren, Lonomia makes itself known with an atmosphere and surface impossibly enriched in various halogens. Even mechanical lifeforms would have a hard time not dissolving in this acid-eaten pit.
Lonomia torments the mortal species with an appeal to uninhabitability.
Observe a world struck by darkness. This ringed terrestrial world does not lie within the traditional habitable zone, but like early Mars, retains vast liquid oceans. A freezing, eutectic mix of water and caustic ammonia fills these seas, far too hostile for any known lifeforms to swim in.
Attacus wills itself to survive, even when the universe conspires against it.

Far Exterior - Sole Member Series

Night City

The hydrogenous limb of Peripatus, underscored by the tremendous brightness of its water-ice rings, pales in comparison to the backlit, incandescent orange transmission of its Titanian moon Thryidopteryx.

Capping off the planetary system of Hexancistra is the gas giant Peripatus, the only gas giant in the system and a poor analogue for Jupiter. Well beyond the inner planets and unable to influence their dynamics, the lone planet lies embedded in a continuous disk of asteroids that extends well inside and well outside its orbit, though it leaves its mark in the form of great ripples and eddies in the invisible sheet.

Members of the Far Exterior

Witness a world incomplete. Far from Hexancistra where Uranus would be in the Solar System, this Saturn-like giant orbits its sun in an eccentric oval heavily tilted to the other planets’ orbital plane, torqued by the immense gravity of the binary brown dwarfs Capsellina and Vampyrella.
Peripatus balances on a razor-thin wire, torn between magnificent forces.

Substellar Provision: Capsellina-Vampyrella, the Chionian Reach

Though the Saturnia System contains only one star, Hexancistra is not totally alone in its journey through the cosmos. With a combined mass 9.4% of the Sun, the twin brown dwarfs Capsellina and Vampyrella are held from stardom solely by the merit of distance. Were they to come together they would make for a proper, if low-mass red dwarf, but as it stands they will remain just two stillborn embers for trillions of years. At present, Capsellina still glows dimly with a light redder than that of any star, while Vampyrella’s 600° surface emits practically nothing in the optical spectrum.

The substellar nature of Capsellina and Vampyrella has not deterred the formation of a planetary system around them. Five circumbinary planets ranging in mass from slightly more than Mars to 30% more than Earth circle their combined center of mass. All are frozen, icy worlds primarily made of water ice, much like the moons of our gas giants or Pluto.

Rule of Two

This magnified shot catches aquarian Acerentomon caught between giants. The still-glowing ember of Capsellina lies overexposed on the left as an amorphous blob of yellow-red light, while burnt-out Vampyrella on the right looks little different from Acerentomon itself.

Friends on the Other Side

Though Hexancistra has long set on this side of Thermobia, the blood-red light of Capsellina casts an eerie shade over this frozen world.

Noonday Stars

The minuscule amount of sunlight frigid Lepisma receives from Hexancistra struggles to drown out the sea of stars that rises behind it, as well as the now-distant pinprick of Capsellina.

Earthen Hues

The tholin-stained basins of Campodea take a form reminiscent of a scream on the twilight limb of this low-mass aquarian world. Little can be seen of the wondrous forms that carpet its surface.

New Horizons

The carbonaceous, black-and-orange crescent of Machilis contrasts with the milky, nitrogenous glaciers of its moon Petrobius. Eternally facing each other, the pair swing through the cosmos together.

Unlike the brown dwarfs of Horizon and Cambria, Capsellina and Vampyrella are closer to stars than planets. The architecture of the entire system is not unlike that of our Epsilon Indi, where a binary pair of brown dwarfs orbits each other at great distance from a normal star. The high mass and great separation of the two from Hexancistra makes it very unlikely that they formed the way planets do, instead collapsing from large gas clouds in the vicinity of the nascent star. Correspondingly, they have formed a fairly impressive planetary system from a circumbinary disk, as do normal stars.

Planets of Capsellina-Vampyrella

Stand testament to a world gone strange. This rapidly-rotating aquaria orbits close to the inner limit of stability around its host binary, resulting in significant variations in its orbit. Massive gravitational torques pull its rotation axis every which way, resulting in irregular seasons and chaotic days.
Acerentomon needs not conceal its actions if it has no idea what it is doing.
Watch a strange world of russet hues. Though the warm colours of Thermobia’s soil might bring to mind torrid deserts and cozy fireplaces, this frigid aquaria is much closer kin to Pluto and Titan than Earth or Venus.
Thermobia reminds the observer that appearances can be deceiving.
Encounter a frigid, mauve analog to a world we find familiar. The lakes of hydrocarbons and liquid nitrogen of this aquarian world bring to mind the similarly lacustric Titan, but this low-density planet is larger than Earth. With only a thin veneer of tholins over a silvery water-ice crust, the skies of this planet remain wonderfully clear.
Lepisma executes a storied vision.
Behold a world of delicate frost. Though this aquarian world has no permanent bodies of liquid, its atmosphere is rich in sublimed volatiles. Deposition from the atmosphere has resulted in a strange landscape of massive spires, enormous snowflakes, and vast carpets of nitrogen-ice ‘silk’.
Campodea carves its heart from the underworld.
Investigate a world forever unchanging. This small aquarian world and its large moon closely resemble a larger version of the Pluto-Charon binary, combined with the same volatile glaciers and rock-solid water ice interior. With thick crusts and low energy budgets, these little worlds have barely moved over a billion years.
Machilis thinks on timescales alien to the likes of we.