Proxima Centauri
The closest known star to the Sun and humanity’s most likely first interstellar destination.
Key Facts
- Distance: 4.2465 ly (1.3012 pc) from Sol
- Type: M5.5Ve red dwarf
- Mass: 0.122 solar masses
- Luminosity: 0.0017 solar luminosities (very dim)
- Part of: dest-alpha-centauri triple system (gravitationally bound)
- Age: ~4.85 billion years
Known Planets
| Planet | Type | Orbit | Mass | Habitable? |
|---|---|---|---|---|
| Proxima b | Rocky | 0.049 AU (11.2 days) | ~1.17 Earth masses | In habitable zone, but see caveats |
| Proxima c | Super-Earth/Mini-Neptune | ~1.49 AU (1,928 days) | ~7 Earth masses | Too cold |
| Proxima d (candidate) | Sub-Earth | 0.029 AU (5.1 days) | ~0.26 Earth masses | Too hot |
Proxima b — The Target
Proxima b sits in the concept-habitable-zone, but habitability is contested:
- For: Right temperature range for liquid water, rocky composition likely
- Against: Proxima Centauri is a flare star — intense X-ray and UV bursts may strip atmosphere. Likely tidally locked (one side always facing star). Stellar wind pressure ~2,000x what Earth receives.
A thick atmosphere or strong magnetic field could protect surface life, but we don’t yet know if either exists.
How To Get There
| Method | Speed | Travel Time | Status |
|---|---|---|---|
| mission-voyager-1 speed (17 km/s) | 0.000057c | ~73,000 years | Proven but impractical |
| tech-ion-drive (advanced) | ~0.01c | ~425 years | In development |
| tech-solar-sail / tech-laser-propulsion | 0.2c | ~21 years | Proposed (mission-breakthrough-starshot) |
| tech-fusion-drive | 0.05–0.1c | ~42–85 years | Theoretical |
| tech-nuclear-pulse (Orion) | 0.03–0.05c | ~85–140 years | Theoretical |
Breakthrough Starshot
The most concrete current plan to reach Proxima: mission-breakthrough-starshot proposes sending gram-scale probes via tech-laser-propulsion at 0.2c, arriving in ~21 years. The probes would fly through the system in seconds, beaming back data via onboard lasers. Signal return time: 4.24 years.
Total mission time from launch to data received on Earth: ~25 years.