Baunerth, formerly Jovia or Cangyuan, is the fourth and largest planet in the Ignis system, orbiting Ignis Prime and Umbra Magna at a distance of 2.55 astronomical units every 1,487.31 sidereal days. With a radius of 74,250 kilometers, Baunerth has a cloud-top gravity more than twice that of Avium's surface gravity (25.29 m/s²) and is characterized by its immense size, extreme atmospheric pressure, and complex weather systems. Its hydrogen-helium atmosphere is dominated by methane and ammonia, forming dense reflective clouds and producing a low average surface temperature of 165 K (-108 °C). Baunerth is orbited by 17 satellites ranging from small captured asteroids to large geologically active moons, and exhibits spiral storm systems caused by tidal interactions with the binary systems.
Nomenclature
The name Baunerth was adopted in 1843 in honor of Arlbernian astronomer Andreas Baunerth, who spent most of his career observing the planet and its moons and documenting his discoveries. Prior to this, the planet had been known by various names across different cultures. In most of Evria, it was called Jovia after a deity from the ancient Rumaic pantheon, while in Serica, it was called Cangyuan (苍渊, “Pale Blue Abyss”).
History
Baunerth has been known since antiquity as one of the brightest objects in the night sky, visible to the naked eye under most conditions. Ancient astronomers from many cultures recorded its wandering motion against the background stars, distinguishing it from the fixed celestial bodies. The earliest surviving records come from the astronomers of the old Divian civilizations around 600 CE, who incorporated Baunerth into their celestial calendars and navigation charts.
In 1628, Vicilian astronomer Vittore Avellino discovered Baunerth’s three largest moons using a telescope, making it the first recorded telescopic observation of moons other than Selene.
Characteristics
Physical Properties
Baunerth is the largest planet in the Ignis system by every measurable metric. Its mean radius is 74,250 kilometers, corresponding to a total volume of 1.7147 × 10¹⁵ km³ and a surface area of 6.9279 × 10¹⁰ km². Despite its enormous mass of 2.0890 × 10²⁷ kg, Baunerth only has an average density of 1.220 g/cm³ and consists mainly of lighter elements such as hydrogen and helium, with only a relatively small proportion of heavier elements concentrated in a probable rocky-metallic core surrounded by metallic hydrogen. Baunerth has a high albedo of 0.52 due to its dense ammonia ice clouds and high-altitude methane haze, which scatter incident light.
Surface Conditions
Baunerth's atmosphere is a hydrogen-helium mix at a cloud-top pressure of 326.3 psi. The bulk composition by volume is: 89.2% hydrogen, 10.1% helium, 0.3% methane, 0.2% ammonia, 0.1% water vapor, 0.1% hydrogen sulfide, and 0.1% other trace gases. These components form a layered structure of clouds and haze, each at a different altitude and temperature. The uppermost visible clouds consist mainly of ammonia ice, giving the planet a pale, reflective appearance. Clouds of ammonium hydrogen sulfide, and water are thought to exist beneath these layers, but they are not visible to direct observation.
Unlike many other gas giants, Baunerth's cloud patterns are not dominated by linear bands, but by giant rotating spiral storms, some of which are more than 40,000 km in diameter. These systems are driven by the planet's relatively rapid rotation, the complex gravitational interactions of its moons, and the tidal forces of Ignis Prime and Umbra Magna. Storms often last for decades, changing shape but retaining their overall structure. High-altitude winds circulate at tremendous speeds, redistributing heat and causing subtle changes in the planet's coloration over time.
Baunerth's cloud-top gravity is approximately 25.29 m/s², the result of its immense mass balanced by its large radius. This high gravity allows the planet to retain its massive, dense atmosphere, even within the relatively energetic environment of a binary system. Baunerth’s magnetic field is generated by a dynamo within its deep metallic hydrogen layer, formed under immense pressures far beneath the upper atmosphere. The field is exceptionally strong and expansive, extending far beyond the planet to encompass many of its moons.
Orbit and Rotation
Baunerth orbits the barycenter of Ignis Prime and Umbra Magna at a mean distance of 2.55 AU, completing one sidereal revolution in 1,487.31 days at an average orbital speed of 38.33 km/s. Its synodic period relative to Avium is 484.15 days. The planet rotates once every 26.84 hours (sidereal), producing a rapid day-night cycle compared to its long orbital period. Baunerth’s axial tilt is 12.4°, producing only minor seasonal variations in its upper cloud patterns.
Baunerth’s 17 natural satellites exert complex tidal interactions within the planet’s deep atmosphere and metallic hydrogen layer. These tidal forces produce measurable modulation of atmospheric jet streams and contribute to the long-term evolution of the moons’ orbits. The four Avellinian moons (Virella, Corvessia, Taurelia, and Nuova Efricia), Baunerth's largest satellites, experience significant orbital perturbations from the combined influence of Baunerth’s magnetosphere and the stellar winds of Ignis Prime and Umbra Magna.
Observation
Baunerth has an apparent magnitude of -6.55, making it prominently visible from Avium. Its brightness is enhanced by the combination of its extensive cloud cover, reflective ammonia ice, and high-altitude methane haze. The planet’s absolute magnitude of −9.53 is the brightest in the Ignis system, caused by its intrinsic reflectivity and large size. Detailed study of its atmospheric patterns, storm systems, and moons requires telescopic imaging and spectroscopic techniques to mitigate interference from the binary star system’s glare.