K2-370 b
Astrophysical Synthesis & Habitability Characterization
K2-370 b is a confirmed sub-neptune exoplanet orbiting the star K2-370, located approximately 470.3 light-years (144.2 parsecs) from the Solar System. First announced in 2022 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.0671% across the stellar disk), this world measures 2.67 Earth radii and has a measured mass of 11.1 Earth masses. Combining its mass and radius yields a mean bulk density of 3.22 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.56 g⊕ (15.3 m/s²), and an escape velocity of 22.8 km/s.
In its orbital architecture around K2-370, K2-370 b completes one full revolution every 2.141 Earth days at a semi-major axis of 0.0321 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 163.1 km/s (compared to Earth's 29.8 km/s). The orbit is modeled as circular (e = 0.00), maintaining a constant stellar distance throughout its year.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1267 K (+994°C / +1821°F) and receiving 428.21 S⊕ (~582,787 W/m²), K2-370 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star K2-370 is classified as a solar-type yellow star of spectral type G5 V with an effective photospheric temperature of 5,662 K, a radius of 0.945 R☉, a mass of 0.962 M☉, an estimated bolometric luminosity of 0.823 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.4 Gyr and a metallicity of [Fe/H] = 0.08 dex (metal-rich relative to the Sun). From Earth, K2-370 shines at apparent V-band magnitude 11.109 (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 | K2-370 |
| Spectral Type | G5 V |
| Effective Temp (Teff) | 5,662 K |
| Stellar Radius | 0.9450 R☉ |
| Stellar Mass | 0.9620 M☉ |
| Bolometric Luminosity | 0.823 L☉ |
| Metallicity [Fe/H] | 0.080 dex |
| Stellar Age | 1.400 Gyr |
| Apparent Magnitude | V: 11.109 · G: 10.882 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.032100 AU |
| Orbital Period | 2.141 days |
| Mean Orbital Velocity | 163.1 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 84.4400° |
| Mean Bulk Density | 3.22 g/cm³ (22.8 km/s vesc) |
| Insolation Flux | 428.2050 S⊕ (~582,787 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 470.300 LY (144.202 pc) |