Space Codex / Exoplanet reference
Published exoplanet measurements
Proxima Cen b
Proxima Cen b orbits Proxima Cen once every 11.1846 days. The system is about 4.24391 light-years from Earth.
Archive retrieved November 1, 2026 (America/New_York). The selected paper and archive update dates appear below.
The recorded orbit
The selected archive solution gives an orbital period of 11.1846 days, or 0.0306219 Earth years. Its reported semimajor axis is 0.04848 AU. That orbital scale is 0.12524 times Mercury's semimajor axis. The listed eccentricity is 0. A zero may be a circular assumption fixed in the fit; consult the paper before treating it as an exact observed shape. The period measures a year on this planet. It does not establish the length of its rotation or the duration of daylight.
Read how orbital period, size, and eccentricity fit together.
Size and mass
No planetary radius is supplied in this selected solution. The profile leaves that gap visible rather than estimating a size from the mass. The mass parameter is 1.055 (+0.055 / −0.055) Earth masses. Its archive provenance is Msini. Read this provenance before comparing it with a true mass: an inclination-dependent minimum or another mass definition must keep its qualification.
The host star and received light
The host is cataloged as Proxima Cen. The selected row gives spectral type M5.5 V. Its reported effective temperature is 2900 K. Its reported radius is 0.141 solar radii. Its reported mass is 0.1221 solar masses. The planet's incident-flux parameter is 0.641 (+0.065 / −0.065) times Earth's received stellar flux. The equilibrium-temperature entry is 218 (+18 / −18) K. This is a model quantity, not a measured surface temperature. The available stellar and orbital entries do not establish a breathable atmosphere, surface water, or life.
What a habitable-zone claim does and does not mean · How a star changes over time.
Other planets around Proxima Cen
The fetched archive contains 2 selected default planet records for this host. This is the retrieved record set, and additional or revised discoveries may appear in later research.
| Planet | Period (days) | Radius (Earth) | Mass parameter (Earth) | Mass definition |
|---|---|---|---|---|
| Proxima Cen d | 5.12338 (+0.00035 / −0.00035) | Not reported in this solution | 0.26 (+0.038 / −0.038) | Msini |
| Proxima Cen b | 11.1846 (+0.00053 / −0.00053) | Not reported in this solution | 1.055 (+0.055 / −0.055) | Msini |
Earth comparison
| Quantity | Reported value or conversion | Comparison |
|---|---|---|
| Orbital period | 11.1846 days | 0.0306219 Earth years |
| System distance | 1.30119 parsecs | 4.24391 light-years |
| Orbital scale | 0.04848 (+0.00029 / −0.00029) | AU; Earth = 1 |
| Mass parameter | 1.055 (+0.055 / −0.055) | Earth masses; check mass definition |
| Received stellar flux | 0.641 (+0.065 / −0.065) | Earth flux; Earth = 1 |
Conversions use rounded central values. They are navigation aids for the data, not additional observations. Uncertainties for the original parameters remain in the next table.
Measurement table
| Parameter | Value and reported uncertainty | Unit or definition |
|---|---|---|
| Orbital period | 11.1846 (+0.00053 / −0.00053) | days |
| Semimajor axis | 0.04848 (+0.00029 / −0.00029) | AU |
| Radius | Not reported in this solution | Earth radii |
| Mass parameter | 1.055 (+0.055 / −0.055) | Earth masses |
| Orbital eccentricity | 0 | dimensionless |
| Orbital inclination | Not reported in this solution | degrees |
| Equilibrium temperature | 218 (+18 / −18) | K; model estimate |
| Incident flux | 0.641 (+0.065 / −0.065) | Earth flux |
| Bulk density | Not reported in this solution | g/cm³ |
| Host effective temperature | 2900 (+100 / −100) | K |
| Host radius | 0.141 (+0.021 / −0.021) | solar radii |
| Host mass | 0.1221 (+0.0022 / −0.0022) | solar masses |
| Host metallicity | Not reported in this solution | dex; archive abundance definition |
| Host age | Not reported in this solution | billion years |
| Host luminosity | -2.82102 (+0.02242 / −0.02364) | log10 solar luminosity |
| Host surface gravity | Not reported in this solution | log10 cm/s² |
| Host rotation period | 83.2 | days |
| System distance | 1.30119 (+0.00034 / −0.00035) | parsecs |
Parentheses show the reported upper and lower uncertainties when both are supplied. Bounds are explicitly labeled. A missing entry means unavailable in this solution, not zero. The confidence convention belongs to the source paper.
Research record and limitations
| Record | Value |
|---|---|
| Planetary reference | Suárez Mascareño et al. 2025 |
| Discovery method | Radial Velocity |
| Discovery year | 2016 |
| Discovery facility | European Southern Observatory |
| Mass provenance | Msini |
| Host stars in system | 3 |
| Archive system planet count | 2 |
| Planetary solution publication date | 2025-08 |
| Row update date | 2025-07-29 |
| Archive release date | 2025-07-29 |
Source: NASA Exoplanet Archive overview for Proxima Cen b, Planetary Systems table, default solution. The collection excludes entries flagged controversial at retrieval. A selected default is a published reference choice, not a claim that every parameter is the latest estimate in all literature.
This profile documents measurements and their scope. It is separate from the 3D planet catalog and does not create a sponsorship placement or a new explorer destination.