K2-167 b
Astrophysical Synthesis & Habitability Characterization
K2-167 b is a confirmed sub-neptune exoplanet orbiting the star K2-167, located approximately 263.9 light-years (80.9 parsecs) from the Solar System. First announced in 2018 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.0209% across the stellar disk), this world measures 2.365 Earth radii and has a measured mass of 6.5 Earth masses. Combining its mass and radius yields a mean bulk density of 2.71 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.16 g⊕ (11.38 m/s²), and an escape velocity of 18.5 km/s.
In its orbital architecture around K2-167, K2-167 b completes one full revolution every 9.979 Earth days at a semi-major axis of 0.0932 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 101.6 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.48, swinging from 0.0485 AU at periapsis out to 0.1379 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1220 K (+947°C / +1737°F) and receiving 317.00 S⊕ (~431,437 W/m²), K2-167 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star K2-167 is classified as a warm F-type star of spectral type F7 V with an effective photospheric temperature of 6,310 K, a radius of 1.499 R☉, a mass of 1.084 M☉, an estimated bolometric luminosity of 3.196 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.3 Gyr and a metallicity of [Fe/H] = -0.456 dex (metal-poor relative to the Sun). From Earth, K2-167 shines at apparent V-band magnitude 8.24 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere.
Methodology: Computed using the Schulze-Makuch et al. (2011) weighted metric comparing physical interior (radius, estimated density) and surface thermal regime (escape velocity, equilibrium temperature).
Discovery Facility: K2 · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | K2-167 |
| Spectral Type | F7 V |
| Effective Temp (Teff) | 6,310 K |
| Stellar Radius | 1.4990 R☉ |
| Stellar Mass | 1.0840 M☉ |
| Bolometric Luminosity | 3.196 L☉ |
| Metallicity [Fe/H] | -0.456 dex |
| Stellar Age | 5.300 Gyr |
| Apparent Magnitude | V: 8.240 · G: 8.104 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.093200 AU |
| Orbital Period | 9.979 days |
| Mean Orbital Velocity | 101.6 km/s |
| Orbital Eccentricity (e) | 0.48000 |
| Orbital Inclination (i) | 86.8000° |
| Mean Bulk Density | 2.71 g/cm³ (18.5 km/s vesc) |
| Insolation Flux | 317.0000 S⊕ (~431,437 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 263.900 LY (80.899 pc) |