Binary stellar system · 10 planets · Former home of the Alf people
Primary star — Asterra
The Asterra star system is dynamically stable and long-settled. Most permanent infrastructure predates the loss of Ytharia and was designed for extended autonomous operation.
1. Keth
Keth exhibits permanent hemispheric contrast — the dayside faces continuous stellar radiation while the nightside remains cold and shielded. Never intended for habitation, it functioned solely as an inner-system industrial node.
| Operational depth | Peak staff | Automation |
|---|---|---|
| 300–1,200 m | <4000 | HIgh |
Facilities: subsurface, hardened · Power: orbital solar collectors and compact reactors
2. Ytharia
The only planet in the Asterra system known to support complex native life. Ytharia was the historical and cultural origin point of the Alf people.
| Orbital altitude | Ring diameter | Pre-loss pop | Capital berths |
|---|---|---|---|
| ~42,000 km | ~11 km | ~180,000 | ~10 |
| Radius | ~1,720 km | Radius | ~720 km |
|---|---|---|---|
| Mass | 0.94 Luna | Distance | ~610,000 km |
| Distance | ~410,000 km | Period | 69.2 days |
| Period | 34.6 days | Resonance | 2:1 with Elaris |
| Base capacity | ~25,000 | Inclination | 3.1° |
3. Vael
Vael's powerful magnetosphere deflected a significant fraction of cometary and interstellar debris, contributing to inner-system stability.
4. Orthis
Several moons show evidence of subsurface oceans or cryovolcanic activity. Orthis hosted the system's primary middle-system logistics hub.
| Orbital altitude | Peak population | Annual throughput |
|---|---|---|
| ~1.8M km | ~95,000 | ~120M tons |
5. Ceryn
Orbital characteristics indicate a major disruption event approximately 1.3 billion years ago, likely responsible for Ceryn's irregular and partially captured moon population.
6. Helior
Helior marks the outer boundary of significant planetary mass in the primary system. Its sparse, frozen satellites are relics of the outer system's early formation.
7. Nysa
A frozen, isolated world at the far edge of the primary system. The lack of satellites is attributed to early orbital instability and gravitational interference from the outer gas giants.
Companion star — Carmyn
Carmyn is the red companion star of the Asterra binary system, orbiting at a wide separation that renders it a naked-eye fixture in Ytharia's night sky — a dim but constant red point, distinct from the stars of the broader field. Its slow drift across centuries of recorded observation made it a cultural and navigational reference point long before its stellar nature was understood.