The Erebos System: The Light, the Dark, and the Hateful
Overview
Presiding over the distant reaches of the intermediate-age Hourglass Cluster near the center of the Comatula Nebula is a truly unique star system. At just over 3 billion years of age, Erebos is young for stars in the universe but a fair age for the thin-disk population of Passiflora and well over the age required to leave its birth cluster. However, a dark beast seems to have persisted as an unlikely hitchhiker in this seemingly-inconspicuous system, for it is one of the rare inhabited black holes on this side of the universe.
Unlike many of the other systems we have come to on our journey, the Erebos System resembles our Solar System in that only a single world in its myriad array hosts life. The biota of its namesake Erebos is relatively primitive but the planet’s thick and moist atmosphere has allowed life to move to land much more easily than it did on Earth. They are not particularly unusual when it comes to biochemistry nor do they seem to possess the complex and sordid histories of other worlds (a la Oceanus), but their existence alone in this burnt-out cinder system is a miracle in and of itself.
Even more remarkable than the survival of life in a system razed by supernova is the presence of intelligent life. The neural forests of Erebos are home to a species of gelatinous, jellyfish-like gasbags who thrive in high-pressure environments. Though their species has been around for an exceptionally long time of at least 6 million years, the lack of sustained fire, wood, and fossil fuels kept them in the Stone Age until less than 10,000 years ago, when they were uplifted by an unknown polity. Though one of the older civilizations in the galaxy, their spacefaring history is interspersed with thousand-year interregnums where it has collapsed for various reasons, before reassembling its former glory in the millennia after. At preset, they are on the Fifth Iteration of their society.
The First Sun: Abyssoaclis, the Might of Gravity
Abyssoaclis is a rarity in that it is a stellar-mass black hole within a life-bearing system. While we ordinarily see supernovae as destructive events inimical to the formation or survival of planets, Abyssoaclis seems to have demonstrably proved this is not necessarily the case. Though it currently has a mass 6.4 times the Sun’s, it probably once had about 30 solar masses when it was alive as a short-lived O star. It is unclear whether Abyssoaclis and Eulima were already in a binary at this time or if the former captured the latter during its natal kick, but in any case they have been together for practically all of their lives. Separated from other stars and sources of gas by the radiative envelope of Eulima, Abyssoaclis has never been active.
With seven planets and a wide debris disk together massing around half a Jupiter, Abyssoaclis has the sort of low-mass planetary system expected from black hole re-accretion, depleted in hydrogen and consisting mostly of alpha elements (O, Mg, Si, S, Ca). A number of them are in pairwise resonant relationships but there is no broad system-wide resonance chain, suggesting that planetary migration was minimal.
Though Abyssoaclis has seven planets of varying size, the strangely haphazard arrangement of planetary types makes it difficult to group them into neat little families. The absence of sunlight evidently has had a strong effect on the formation of Abyssoaclis’s planets; gas giant Cryptotora bumps shoulders with terrestrial Leptodirus exterior to the icy wastes of Sinocallipus, just to name a few unusual characters.
Planets of Abyssoaclis
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Swing by a world testament to a now-vanished power. Though this small terrestrial world broadly resembles the others of its family, a thin dusting of tholins from the carbonaceous inner asteroid belt stains its oceans a brilliant neon, a testament to the origin of this coat of stardust.
Hausera sulks in the darkest depths.
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Investigate a curious world with seas of liquid air. Heated only minimally by distant Eulima, this massive terrestrial world’s once-thick atmosphere has almost completely collapsed down to the surface, with remnant hydrogen ensuring a powerful greenhouse effect that keeps its seas liquid.
Zospeum drowns in frigid silence.
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Travel to a grand extension of a familiar face. This aquarian world with its great tholinaceous escarpments, nitrogenous plains and cryogenic seas closely resembles a more massive, more active version of our Pluto. Perhaps it formed in the same way, condensing from the heterogenous soup of material tossed outwards by Hausera and Zospeum.
Sinocallipus gropes blindly through the dark.
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Marvel in the grandeur of an angelic giant. This low-mass gas giant distinguishes itself with an enormous disk of fine ice saved from erosion by the enormous distance from Eulima. Three atmosphere-bearing moons draw spiraling ripples through this ethereal cloak.
Cryptotora dances in the raging stream.
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Encounter a cold mockery of Earth. Though it sits at a frigid -200°C, this terrestrial world closely resembles a slightly more massive version of our blue planet, with widely-spread continents, white puffs of cloud, and deep cerulean seas. Only here, those seas are made of bone-chilling nitrogen.
Leptodirus deceives the naive and feasts on their corpses.
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Fly past a strange world of snow and ice. This massive, ringed super-aquaria draws an eerie parallel with its atmospheric moon Antrolana, which runs so cold that even noble neon freezes and sinks into a lunar sea.
Iuiuniscus constructs a world of its own creation.
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Come upon a gaseous dwarf, just four times the mass of Earth yet cloaked in clouds of frigid hydrogen. Its clouds take on the pinkish shades of frozen neon while its three main moons draw blood-red crescents in the skies, stained with the dull rust of sun-baked tholins.
Typhliasina dances joyfully through the eternal dark.
The Second Sun: Eulima, the Unwilling Puppet
In contrast to the exotic and sordid history of Abyssoaclis, Eulima is practically boring. This F9 white star displays no major variability, no significant chemical abnormalities, nor an anomalous appearance. It does however retain traces of a highly unusual past.
The planetary system of Eulima is quite limited, with only four planets. It is extremely asymmetric, with almost all the mass consolidated into the super-Jupiter Desulforudis while the other planets combined do not exceed much more than 5 Earth masses. There are signs however that this was not always the case; the giant Desulforudis has an exceptionally extended core suggestive of a massive collision in its deep past. The planets are also all heavily enriched in high-weight isotopes, suggesting severe ablation probably from the supernova that made Abyssoaclis. The planets are also quite enriched in carbonaceous material as are the ones around Abyssoaclis, suggesting a carbon star or some other source of the element must have been involved in their formation. Possibly one was involved in a three-body interaction that helped Abyssoaclis capture Eulima before falling into the black hole and being slung around the system, though the likelihood of this happening outside a dense cluster environment is quite low.
Though Eulima’s planetary system is much neater than its companion’s and indeed closely resembles that of our Solar System, each class of planet is really represented by only a single member. It would be inappropriate to claim each world as the sole member of its own series, so none are assigned.
Planets of Eulima
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Gaze upon the scarred face of a sulfurous, lava-struck world. This golden orb has only recently solidified after furiously purging its ancient surface, but already new pockmarks of active volcanism mar its basalt-blasted skin. As the fresh shields of volcanic provinces rise thousands of meters above the desert rocks, the cycle of regeneration begins anew.
Halicephalobus scrapes and scratches its ruined skin in vain.
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Observe a world of rare beauty, shrouded in an aerial sea. The thick, moist atmosphere of this super-Earth cultivates vast, writhing forests of terrestrial algae and maze-like reefs of stromatolites that play home to all sorts of strange things that crawled eons ago from the eldritch sea.
Erebos languidly drifts in a sea of spores.
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Witness a giant of rare ambition. This massive super-Jupiter hosts a practically endless array of carbonaceous moons from tiny chondritic scraps to eight tar-soaked worlds. Polluted with hydrocarbon smog yet blinged-out with vast fields of diamond, these wonderful contradictions make for a truly unique world, even among the Authors.
Desulforudis sings the song of the boldest wanderers.
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Glance at a little world of strange origin. This Pluto-like aquarian world sits at the very edge of stability, teetering between the gravitational abyss of Abyssoaclis and the perturbing influence of Desulforudis. In strange times yet to come, it may even find itself switching its allegiances between them.
Lithopythium faces a dilemma of who it ought to be.
