K2-107 b
Astrophysical Synthesis & Habitability Characterization
K2-107 b is a confirmed gas giant exoplanet orbiting the star K2-107, located approximately 2234.8 light-years (685.2 parsecs) from the Solar System. First announced in 2017 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.6551% across the stellar disk), this world measures 15.98 Earth radii (1.43 Jupiter radii) and has a measured mass of 266.977 Earth masses (0.84 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.36 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.05 g⊕ (10.3 m/s²), and an escape velocity of 45.7 km/s.
In its orbital architecture around K2-107, K2-107 b completes one full revolution every 3.314 Earth days at a semi-major axis of 0.0475 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 155.9 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 1649 K (+1376°C / +2509°F) and receiving 1,291.43 S⊕ (~1,757,632 W/m²), K2-107 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star K2-107 is classified as a warm F-type star of spectral type F9 IV with an effective photospheric temperature of 6,061 K, a radius of 1.81 R☉, a mass of 1.3 M☉, an estimated bolometric luminosity of 3.967 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.25 Gyr and a metallicity of [Fe/H] = 0.14 dex (metal-rich relative to the Sun). From Earth, K2-107 shines at apparent V-band magnitude 13.012 (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 | K2-107 |
| Spectral Type | F9 IV |
| Effective Temp (Teff) | 6,061 K |
| Stellar Radius | 1.8100 R☉ |
| Stellar Mass | 1.3000 M☉ |
| Bolometric Luminosity | 3.967 L☉ |
| Metallicity [Fe/H] | 0.140 dex |
| Stellar Age | 4.250 Gyr |
| Apparent Magnitude | V: 13.012 · G: 12.767 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.047500 AU |
| Orbital Period | 3.314 days |
| Mean Orbital Velocity | 155.9 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 82.3611° |
| Mean Bulk Density | 0.36 g/cm³ (45.7 km/s vesc) |
| Insolation Flux | 1291.4267 S⊕ (~1,757,632 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2234.800 LY (685.200 pc) |