K2-86 b
Astrophysical Synthesis & Habitability Characterization
K2-86 b is a confirmed super-earth exoplanet orbiting the star K2-86, located approximately 843.8 light-years (258.7 parsecs) from the Solar System. First announced in 2016 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.0559% across the stellar disk), this world measures 1.96 Earth radii and has a measured mass of 4.5 Earth masses. Combining its mass and radius yields a mean bulk density of 3.3 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.17 g⊕ (11.47 m/s²), and an escape velocity of 16.9 km/s.
In its orbital architecture around K2-86, K2-86 b completes one full revolution every 8.777 Earth days at a semi-major axis of 0.077 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 95.4 km/s (compared to Earth's 29.8 km/s).
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 830 K (+557°C / +1035°F) and receiving 78.00 S⊕ (~106,158 W/m²), K2-86 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star K2-86 is classified as a stellar host with an effective photospheric temperature of 5,482 K, a radius of 0.76 R☉, a mass of 0.79 M☉, an estimated bolometric luminosity of 0.468 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.35 dex (metal-poor relative to the Sun). From Earth, K2-86 shines at apparent V-band magnitude 13.041 (faint and requiring research-grade or CCD telescopic photometry) in the Northern 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 | K2-86 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,482 K |
| Stellar Radius | 0.7600 R☉ |
| Stellar Mass | 0.7900 M☉ |
| Bolometric Luminosity | 0.468 L☉ |
| Metallicity [Fe/H] | -0.350 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 13.041 · G: 12.798 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.077000 AU |
| Orbital Period | 8.777 days |
| Mean Orbital Velocity | 95.4 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 88.5604° |
| Mean Bulk Density | 3.3 g/cm³ (16.9 km/s vesc) |
| Insolation Flux | 78.0000 S⊕ (~106,158 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 843.800 LY (258.699 pc) |