Contact binary system in Antlia

S Antliae
Image from Steve Bowers
S Antliae is a contact binary star. The two stars share material and are slowly spiralling towards each other

Freedonia (S Antliae) System

StarsNames: Freedonia
Components: 2 (Contact Binary)
1) Freedonia (S Antliae A)
2) Libertia (S Antliae B)
- Distance from Sol: 260.7 ly (J2000)
- Constellation: Antlia

Names: Freedonia, S Antliae A, HD 82610 A, HIP 46810 A, HR 3798 A
Physical characteristics:
- Mass: 1.94 x Sol
- Radius: 2.026 x Sol
- Luminosity: 13.69 x Sol (bolometric)
- Temperature: 7,800 Kelvin
- Spectral type: A8V
- Age: 6 billion years

Names: Libertia, S Antliae B, HD 82610 B, HIP 46810 B, HR 3798 B
Physical characteristics:
- Mass: 0.76 x Sol
- Radius: 1.322 x Sol
- Luminosity: 4.570 x Sol (bolometric)
- Temperature: 7,340 Kelvin-- Spectral type: A9V
- Age: 6 billion years

Freedonia-Libertia binary orbit
Orbital characteristics:
- Average separation: 2,300,000 km
- Period: 15.6 hr
- Eccentricity: 0.66
1) Losenbasen: AmmonoJovian

Semi-major axis = 9.41 AU
Orbital period = 17.56 years
Eccentricity = 0.31
Inclination from binary plane 65 degrees
Mass = 0.356 x Jupiter
Radius = 61015 km ( 9.57 x Earth )
Obliquity 19 degrees
Rotational period 12.8 hours
Irradiance from star 0.2 x Earth
Moons Tacolia Radius 2101 km
Hautna Radius 1981 km

2) Atmen: CryoAzurianJovian

Semi-major axis =27.7 AU
Orbital period = 0.196 years
Eccentricity = 2.74
Inclination from binary plane 74 degrees
Mass = 0.21 x Jupiter
Radius = 45313 km
Obliquity 23.1 degrees
Rotational period 12.8 hours
Irradiance from star 0.059 x Earth
Moon Sylvania
The S Antliae system was colonised in 2477 AT by a joint NoCoZo/Sophic League mission, drawn by the unusual characteristics of this double star. Although the two components of this star were once very different in temperature and spectral type, they have slowly spiralled closer together over time until they are in contact, becoming a contact binary with a common photosphere. Both elements of this star now shine with the spectral characteristics of an A-type star, although they are different in size and luminosity. These two stars together form a so-called W Ursae Majoris variable object, with a distinct luminosity curve as seen from certain angles.

This system contains two gas giants in wide, eccentric, highly inclined orbits; Losenbasen, an Ammono-Jovian world, and Atmen a CryoAzurian-Jovian world. Any planets which may have existed closer to the stellar pair have been ejected or subsumed as the pair grew closer together, due to various momentum exchange mechanisms. Both giant planets have a wide range of different types of moons which have been colonised in various ways or mined for the construction of habitats and spacecraft. The joint NoCoZo/Sophic administration named this system Freedonia, but after two centuries they declared themselves independent of both empires and seceded from Sephirotic influence.

In 2844 the Freedonian Expansion Initiative sent a colony mission towards TYC 7212-290-1, a system with a rich debris field more than five hundred light years further into the Antlia sector. This colony became Avanola, the gateway to the Xacounian Expansion. The FEI also colonised half-a-dozen other systems in outer Antliae, eventually leading to the establishment of the Gentry Hardline Polity and the Zendart Dominion. But Freedonia itself became little more than a stepping stone to these independent, rival empires, especially as it was on the wormhole trunk-route that led to them..
Image from Steve Bowers
Losenbasen, a gas giant in this system
By the ComEmp era most of the population of Freedonia lived in a cloud of habitats surrounding Losenbosen and Atmen, and on the moons Taconia, Hautna and Sylvania. A significant population of bioist devotees had migrated into organic bubblehabs in the atmosphere of Losenbosen, but this group was gradually isolating itself from outside contact. By 7500 they were completely uncommunicative, and a contact mission into the cloud layers of this planet found that they had completely disappeared.

The autonomous bubblehabs remained active however, and by 7600 a new population of modosophonts had made their homes in these capacious structures. But in due course the new tenants determined that the previous occupants had not left, but instead they still existed in the memories and dreams of the organic habitats. In most cases the new tenants have become quite accustomed to the shadowy presence of these wandering memories.

Sunrise in Freedonia
Image from Steve Bowers
Sunrise in Freedonia
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Development Notes
Text by Steve Bowers
Initially published on 31 October 2020.

Freedonia and Sylvania are named after imaginary countries in the Industrial Age movie Duck Soup.