Mini-Neptune · Kapteyn

Kapteyn c

ExoplanetsDiscovered 2014

Scientific overview

Kapteyn c is a mini-neptune orbiting Kapteyn, completing an orbit every 122 days, about 13 light-years from Earth. It was discovered in 2014 using the radial velocity method.

Host star

Kapteyn

Spectral type

M2.0V

Temperature

3,550 K

Mass

0.281 M☉

Discovery and detection

Detection method

Radial Velocity Method

Discovery year

2014

Knowledge connections

OrbitsKapteyn
Discovered by methodRadial Velocity Method
Catalogued inNASA Exoplanet Archive

Quick facts

Class: Mini-Neptune
Host star: Kapteyn
Discovery method: Radial Velocity Method
Discovery year: 2014
Orbital period: 121.54 d
Semi-major axis: 0.311 AU
Eccentricity: 0.23
Radius: 2.54 R⊕
Mass: 7 M⊕
Density: 2.36 g/cm³ · derived
Equilibrium temp.: 166 K
Insolation: 0.17 S⊕
Distance: 13 ly

Density is derived from the archive mass and radius via ρ = M / (4⁄3·π·r³); all other values are catalogued measurements.

Derived values

Computed from source-backed inputs via standard formulae — not observations. Every input and constant is traced below.

Bulk density2.36 g/cm³derived
Formula & inputs
Formula: ρ = M / (4⁄3·π·r³) (v1.0.0, impl v1.0.0)
Inputs:
- massEarth = 7 M⊕ · NASA
- radiusEarth = 2.54 R⊕ · NASA
Assumptions: M⊕ = 5.972e+24 kg, R⊕ = 6371000 m (IAU 2015 B3 nominal); Assumes a uniform sphere.
Limitations: Withheld above 30 g/cm³ (inconsistent mass/radius inputs).; Archive mass/radius carry no propagated uncertainty here.
Uncertainty: not propagated (inputs carry no catalogued uncertainty)
Computed as of 2026-06-29.

Quality & authority

Partial

Unreviewed

Description: Complete
Source coverage: Partial
Relationship coverage: Complete
Review coverage: None
Citation coverage: None
Image coverage: Not applicable

Data from the NASA Exoplanet Archive. See source quality.