Habitable-zone candidate
Proxima Centauri
Our nearest stellar neighbour hosts a potentially habitable terrestrial world.
- Planets
- 2
- Distance
- 4.2 ly
- Host
- M-type
About Proxima Centauri
Discovery
Proxima Centauri b was announced in 2016 by the ESO-led Pale Red Dot campaign, which used radial-velocity measurements from the HARPS spectrograph to detect an Earth-mass planet around the nearest star to the Sun.
Why it matters
At 4.24 light-years away, Proxima b is the closest potentially habitable exoplanet we will ever find — making it the realistic first target for any future interstellar mission concept like Breakthrough Starshot.
Current research
Follow-up radial-velocity work has confirmed a third planet, Proxima d, and constrained the system's architecture; direct-imaging attempts with ground-based ELTs are the long-term plan to characterize Proxima b's atmosphere.
Comparable to
If the Sun were in New York, Proxima Centauri would be the next streetlamp over — and it has a roughly Earth-mass planet in its habitable zone.
System geometry
At a glance
- Hostname
- Proxima Cen
- Spectral type
- M5.5 V
- Distance
- 4.2 ly · 1.30 pc
- Stellar mass
- 0.12 M☉
- Stellar radius
- 0.14 R☉
- Luminosity
- 1.51e-3 L☉
- Effective temp
- 2900 K
- Confirmed planets
- 2
- Habitable zone
- 0.037 – 0.053 AU
Top-down orbital diagram
Orbits to scale within this system. Dashed green = habitable-zone edges.
Planet positions are illustrative (evenly spaced in phase). For live motion see the 3D scene.
The planets
2 confirmed.
Rocky world
Proxima Cen d
- Orbit
- 0.029 AU
- Period
- 5.12 days
- Radius
- 0.69 R⊕
- Mass
- 0.26 M⊕
- Eq. temperature
- 282 K
- Eccentricity
- 0.000
- Discovered
- 2025 · Radial Velocity
Rocky world
Proxima Cen b
- Orbit
- 0.048 AU
- Period
- 11.18 days
- Radius
- 1.02 R⊕
- Mass
- 1.05 M⊕
- Eq. temperature
- 218 K
- Eccentricity
- 0.000
- Discovered
- 2016 · Radial Velocity
Compared to our Solar System
Each row shows the closest Solar-System analog by radius (log-space). Earth is pinned at the bottom as the constant frame of reference.
| Planet | Radius (R⊕) | Mass (M⊕) | Orbit (AU) | Period (days) | Eq temp (K) | Solar analog |
|---|---|---|---|---|---|---|
| Proxima Cen d | 0.69 | 0.26 | 0.029 | 5.12 | 282 | Mars |
| Proxima Cen b | 1.02 | 1.05 | 0.048 | 11.18 | 218 | Earth |
| Earth (reference) | 1.00 | 1.00 | 1.000 | 365.25 | 255 | — |
Research status
◇ JWST observation status
No JWST programs are currently targeting planets in this system. The system may be observed in future cycles or by upcoming missions (Ariel, HWO, Roman).
Discovery timeline
- 2016
Proxima Cen b
via Radial Velocity
- 2025
Proxima Cen d
via Radial Velocity
If you liked this
Other systems in the same theme:
TRAPPIST-1
7 planets · 40.5 ly · M8.0 V
Seven Earth-sized planets around an ultracool dwarf — three in the habitable zone.
Kepler-186
5 planets · 579.2 ly · M1
First Earth-sized planet found in another star's habitable zone (2014).
Kepler-442
1 planets · 1193.6 ly · G2V
One of the most "Earth-like" planets ever found by Kepler — 60% bigger, in HZ.
Related reading
Articles mentioning Proxima Centauri:
Experience it
See Proxima Centauri in interactive 3D
Fly through the system, click any planet, watch orbits play out at 100× speed.
▶ Launch 3D scene