K2-70 b
Astrophysical Synthesis & Habitability Characterization
K2-70 b is a confirmed sub-neptune exoplanet orbiting the star K2-70, located approximately 759.8 light-years (232.96 parsecs) from the Solar System. First announced in 2016 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.0812% across the stellar disk), this world measures 2.89 Earth radii and has a measured mass of 8.7 Earth masses. Combining its mass and radius yields a mean bulk density of 1.99 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.04 g⊕ (10.2 m/s²), and an escape velocity of 19.4 km/s.
In its orbital architecture around K2-70, K2-70 b completes one full revolution every 13.979 Earth days at a semi-major axis of 0.1112 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 86.5 km/s (compared to Earth's 29.8 km/s).
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 784 K (+511°C / +952°F) and receiving 62.00 S⊕ (~84,382 W/m²), K2-70 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star K2-70 is classified as a stellar host with an effective photospheric temperature of 5,622 K, a radius of 0.93 R☉, a mass of 0.94 M☉, an estimated bolometric luminosity of 0.775 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.06 dex (metal-rich relative to the Sun). From Earth, K2-70 shines at apparent V-band magnitude 13.074 (faint and requiring research-grade or CCD telescopic photometry) 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 | K2-70 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,622 K |
| Stellar Radius | 0.9300 R☉ |
| Stellar Mass | 0.9400 M☉ |
| Bolometric Luminosity | 0.775 L☉ |
| Metallicity [Fe/H] | 0.060 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 13.074 · G: 12.778 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.111200 AU |
| Orbital Period | 13.979 days |
| Mean Orbital Velocity | 86.5 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 89.1451° |
| Mean Bulk Density | 1.99 g/cm³ (19.4 km/s vesc) |
| Insolation Flux | 62.0000 S⊕ (~84,382 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 759.800 LY (232.964 pc) |