Hemere

An ice giant planet broadly similar to Uranus and Neptune, Hemere is the closest gravitationally rounded body to the orange dwarf star Hestia. While the cloud tops of Hemere are mainly composed of water vapor, dilute sulfuric acid makes up much of the remainder. The chemistry behind how Hemere’s sulfuric acid may have formed is still a contentious matter, and one of the main drivers of research missions to the scorching world.

As a whole, the body of exoplanet data available from studying Hemere remains one of the planet’s main drivers of immigration. Still, it hasn’t been a compelling enough motivator for potential emigrants to raise the Hemeric population above a few hundred people, most working in hydrogen collection or as members of government.

While the former is an enterprise largely focused for the inhabitants of Hemere’s lunar system(as most Hestians source their hydrogen from another, more densely populated world), the latter is a practice largely derived from the Jovian system’s method of governance. As placing central administrative and governmental habitats on a moon was considered by many Jovian officials to serve as “detracting from the unity of their lunar system”, these core administrative habitats were largely located on the gas giant proper. Granted, this move was seen by many as being much more symbolic than genuinely practical, as the hassles of setting up and maintaining an entire aerial governmental complex on the cloud tops of a very high-gravity gas giant eventually led to the Jovian seat of power moving to a hollowed-out asteroidial moon. Still, the metaphor of the Jovian government as the gravitational parent of its moons presented by Jupiter’s cloud-city capitol was certainly a potent one. Because of this, the settlers of Hemere would find this a powerful way to strengthen the authority of Hemeric governance, which was frayed enough by the deficit of substantial infrastructure to provoke the most desperate ideas.

It also helps that most of Hemere’s settlers had experience with building aerial settlements, owing to their majority-Venusian heritage. The demographics of Hemere also include a small Mercurian minority as well.

As has been previously mentioned, Hemere has a handful of moons, 10 of which are small asteroidial metallic bodies in elliptical and inclined orbits. The other two are worlds comparable in mass to the Solar System’s terrestrial planets, whose gravitational perturbations in conjunction with those of nearby Hestia are likely to blame for the low amount of moons surrounding Hemere. These are Iragea and Vespera, worlds whose unique environments has made them a major draw of immigrants to the Hestian system.

Vespera

The closer and smaller of Hemere’s pair of rounded moons, Vespera is a terrestrial world roughly a third of Earth’s mass, bearing a thick CO₂-dominated atmosphere that renders it surface scorching-hot. For this reason it has been compared frequently to Venus, but the thinner atmosphere and lower gravity are notable differences Venusian colonization efforts constantly work to circumvent. In contrast to the geologically stagnant Venus, Vespera has a hyperactively volcanic surface caused by Hemere’s tidal forces, whose outgassings have given the moon its thick atmosphere. However, along with dangerous lava flows come precious metals and the abundant geothermal energy to power intensive mining operations. Such operations are Vespera’s man source of income, though the high metal content of most Hemeric asteroidial moons has limited the niches for Vesperan metal mining.

Iragea is further away and more massive than its cousin Vespera, though both are similar in that they’re quite likely to be captured terrestrial worlds. In a way, they’re comparable to Earth and Venus; Vespera’s resemblance to the latter has been previously focused on, but Iragea’s atmosphere, hydrology, vigorous tectonics, and native biota have attracted a thriving community of scientists and even civilian immigrants that make it the second most populous body in the Hestian system. Though it’s much smaller than humanity’s homeworld, Iragea has managed to maintain a higher level of tectonic activity through the same tidal forces that rendered Vespera a burnt mini-Venus.

Despite being deemed by many as a “second Earth”, Iragea is far from a habitable world for humanity, let alone a hospitable or comfortable one. Teetering near the edge of a greenhouse meltdown, much of Iragea is uncomfortably humid and stifling even for those native to Earth’s tropics, except when volcanic particulates—caused by a ring of active volcanic complexes facing Hemere, nearly omnipresent in the atmosphere—build up to such a degree so as to cause a micro-ice age worldwide.

Iragea’s largely microscopic biota is another cause for concern, whose uncanny genetic similarities to Earth life have allowed for strains of debilitating Iragean pathogens to emerge. The biocompatibility between Iragean and Earth organisms is regarded by many academics to be a sign that life on both worlds has a common origin, often through Earth microbiota being carried via asteroid impact to Iragea via wormhole(a process known as panspermia). Some hypothesize such an event to have happened in reverse, but this assumption is greatly disregarded. This is due to Iragea’s biosphere being in what seems to be the earliest stages of development, with only a few photosynthesizing microorganisms to create meager oxygen—2% of the total atmosphere.

Despite all these debilitating downsides, however, Iragea’s status as the single most Earthlike celestial body in the entirety of the Hestia system has made it a hub for scientific study, from geology research centers scattered around the moon’s numerous active volcanoes, to floating microbiological labs that study the largely aquatic ecosystems. And indeed, many travelers from Earth flock to the exotic moon as well—most just as part of a tour, but some to stay on a world so similar to home, yet so incredibly different.