K2-320 b
Astrophysical Synthesis & Habitability Characterization
K2-320 b is a confirmed sub-neptune exoplanet orbiting the star K2-320, located approximately 354.7 light-years (108.74 parsecs) from the Solar System. First announced in 2020 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.6411% across the stellar disk), this world measures 2.62 Earth radii and has a measured mass of 7.37 Earth masses. Combining its mass and radius yields a mean bulk density of 2.26 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.07 g⊕ (10.49 m/s²), and an escape velocity of 18.8 km/s.
In its orbital architecture around K2-320, K2-320 b completes one full revolution every 1.995 Earth days at a semi-major axis of 0.0142 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 77.4 km/s (compared to Earth's 29.8 km/s).
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 698 K (+425°C / +797°F) and receiving 37.17 S⊕ (~50,583 W/m²), K2-320 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star K2-320 is classified as a stellar host with an effective photospheric temperature of 3,157 K, a radius of 0.3 R☉, a mass of 0.117 M☉, an estimated bolometric luminosity of 0.00802 L☉. From Earth, K2-320 shines at apparent V-band magnitude 17.81 (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 | K2-320 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 3,157 K |
| Stellar Radius | 0.3000 R☉ |
| Stellar Mass | 0.1170 M☉ |
| Bolometric Luminosity | 0.00802 L☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | — |
| Apparent Magnitude | V: 17.810 · G: 16.355 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.014200 AU |
| Orbital Period | 1.995 days |
| Mean Orbital Velocity | 77.4 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 87.8400° |
| Mean Bulk Density | 2.26 g/cm³ (18.8 km/s vesc) |
| Insolation Flux | 37.1662 S⊕ (~50,583 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 354.700 LY (108.740 pc) |