Alpha Centauri System
Triple-star system with binary dynamics, confirmed exoplanets, and speculative bodies for gameplay.
Overview
Alpha Centauri is the nearest star system to Sol at 4.37 light-years. It is a hierarchical triple system:
- Alpha Centauri A (G2V) and Alpha Centauri B (K1V) form a close binary with a ~80-year period
- Proxima Centauri (M5.5Ve) orbits the AB pair at ~12,950 AU, essentially stationary on game timescales
The A-B binary is modeled with full N-body dynamics. Planet orbits are stable within the circumprimary zones of each star.
Stars
| Body | Spectral Type | Mass (kg) | Radius (m) | Color |
|---|---|---|---|---|
| Alpha Centauri A | G2V | 2.198×10³⁰ (1.1 M☉) | 8.519×10⁸ | #FFF0E0 |
| Alpha Centauri B | K1V | 1.858×10³⁰ (0.93 M☉) | 6.011×10⁸ | #FFD4A0 |
| Proxima Centauri | M5.5Ve | 2.427×10²⁹ (0.12 M☉) | 1.074×10⁸ | #FFB46B |
A-B Binary Orbital Elements
| Parameter | Value |
|---|---|
| Semi-major axis | 23.78 AU (3.558×10¹² m) |
| Eccentricity | 0.524 |
| Period | 79.91 years |
| Inclination | 79.32° |
| Longitude of ascending node (Ω) | 204.75° |
| Argument of periapsis (ω) | 232.3° |
| Epoch of periastron | ~1875.66 |
At J2000 epoch, the binary is near apastron with ~34.7 AU separation. Mass ratio q = M_B/M_A = 0.8453.
Proxima Centauri
Proxima orbits the AB barycenter at ~12,950 AU. At this distance, its orbital period is ~550,000 years. For game purposes it is treated as nearly stationary with a small tangential velocity (~0.3 km/s).
Confirmed Planets
| Body | Parent | Mass (kg) | Radius (m) | Semi-major axis | Period | Notes |
|---|---|---|---|---|---|---|
| Proxima b | Proxima Centauri | 6.39×10²⁴ (1.07 M⊕) | 6.53×10⁶ | 7.27×10⁹ m (0.049 AU) | 11.19 d | Habitable zone, tidally locked |
| Proxima d | Proxima Centauri | 1.55×10²⁴ (0.26 M⊕) | 4.18×10⁶ | 4.32×10⁹ m (0.029 AU) | 5.12 d | Inner rocky |
Speculative Planets (Gameplay)
These planets are not confirmed but placed in dynamically stable zones for gameplay variety. Marked as speculative in all documentation.
| Body | Parent | Mass (kg) | Radius (m) | Semi-major axis | Notes |
|---|---|---|---|---|---|
| Chiron | Alpha Centauri A | 8.96×10²⁴ (1.5 M⊕) | 7.52×10⁶ | 1.87×10¹¹ m (1.25 AU) | Habitable zone, primary destination |
| Erebus | Alpha Centauri A | 3.58×10²⁴ (0.6 M⊕) | 5.50×10⁶ | 8.98×10¹⁰ m (0.6 AU) | Hot Venus-like |
| Nyx | Alpha Centauri B | 7.17×10²⁴ (1.2 M⊕) | 6.94×10⁶ | 1.06×10¹¹ m (0.71 AU) | Habitable zone of B |
| Tartarus | Alpha Centauri B | 2.09×10²⁵ (3.5 M⊕) | 9.80×10⁶ | 4.49×10¹⁰ m (0.3 AU) | Hot super-Earth |
| Proxima e | Proxima Centauri | 4.78×10²⁴ (0.8 M⊕) | 5.96×10⁶ | 2.24×10¹⁰ m (0.15 AU) | Outer rocky |
| Proxima f | Proxima Centauri | 2.99×10²⁵ (5.0 M⊕) | 1.39×10⁷ | 4.49×10¹⁰ m (0.3 AU) | Mini-Neptune |
Moons
| Moon | Parent | Mass (kg) | Radius (m) | Semi-major axis | Notes |
|---|---|---|---|---|---|
| Chiron I | Chiron | 2.99×10²² | 2.00×10⁶ | 5.0×10⁷ m | Rocky moon |
| Nyx I | Nyx | 1.79×10²² | 1.68×10⁶ | 4.0×10⁷ m | Icy moon |
| Proxima e I | Proxima e | 1.19×10²² | 1.46×10⁶ | 3.0×10⁷ m | Tiny moon |
Stable Orbital Zones
Circumprimary planets must orbit within the stability limit ≈ 0.3 × a_binary. For A-B (a=23.78 AU), this gives ~7 AU around each star — all speculative planets are well within this limit.
Stations
| Station | Location | Altitude | Purpose |
|---|---|---|---|
| Centauri Station | Chiron orbit | 400 km | Main hub, docking/refueling |
| Proxima Outpost | Proxima b orbit | 200 km | Remote outpost |
Jump Gates
| Gate | Location | Connection |
|---|---|---|
| Centauri Gate | Chiron orbit | Connects to Sol Gate |
Spawning
Players who select Alpha Centauri at registration spawn near the default infrastructure in Chiron orbit. The default spawn body is Chiron.
Spawn Priority
- Centauri Gate (jump gate) — if present, spawn in co-orbit
- Centauri Station — if gate is missing, spawn near station
- Chiron orbit — fallback: ~400 km altitude circular orbit
Default Infrastructure
The tick-engine spawns the following at game start:
| Entity | Type | Location | Details |
|---|---|---|---|
| Centauri Station | Station | Chiron orbit, 400 km | Main hub |
| Proxima Outpost | Station | Proxima b orbit, 200 km | Remote outpost |
| Centauri Gate | Jump Gate | Chiron–Chiron I L4 | Inter-system travel |
Galaxy View Position
- Direction from Sol (ICRF): [-0.374, -0.313, -0.873]
- Distance: 4.37 ly = 4.132×10¹⁶ m
- Position: [-1.545×10¹⁶, -1.293×10¹⁶, -3.606×10¹⁶] m