K2-140 b
Astrophysical Synthesis & Habitability Characterization
K2-140 b is a confirmed gas giant exoplanet orbiting the star K2-140, located approximately 1134.8 light-years (347.92 parsecs) from the Solar System. First announced in 2017 by K2 using the Transit detection technique (producing an estimated primary transit depth of 1.3761% across the stellar disk), this world measures 13.563 Earth radii (1.21 Jupiter radii) and has a measured mass of 295.58 Earth masses (0.93 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.65 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.61 g⊕ (15.79 m/s²), and an escape velocity of 52.2 km/s.
In its orbital architecture around K2-140, K2-140 b completes one full revolution every 6.569 Earth days at a semi-major axis of 0.068 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 112.6 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 962 K (+689°C / +1272°F) and receiving 204.00 S⊕ (~277,644 W/m²), K2-140 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star K2-140 is classified as a solar-type yellow star of spectral type G6 V with an effective photospheric temperature of 5,585 K, a radius of 1.06 R☉, a mass of 0.96 M☉, an estimated bolometric luminosity of 0.981 L☉. Stellar evolution modeling indicates an estimated stellar age of 9.8 Gyr and a metallicity of [Fe/H] = 0.1 dex (metal-rich relative to the Sun). From Earth, K2-140 shines at apparent V-band magnitude 12.727 (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 | K2-140 |
| Spectral Type | G6 V |
| Effective Temp (Teff) | 5,585 K |
| Stellar Radius | 1.0600 R☉ |
| Stellar Mass | 0.9600 M☉ |
| Bolometric Luminosity | 0.981 L☉ |
| Metallicity [Fe/H] | 0.100 dex |
| Stellar Age | 9.800 Gyr |
| Apparent Magnitude | V: 12.727 · G: 12.481 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.068000 AU |
| Orbital Period | 6.569 days |
| Mean Orbital Velocity | 112.6 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.3000° |
| Mean Bulk Density | 0.65 g/cm³ (52.2 km/s vesc) |
| Insolation Flux | 204.0000 S⊕ (~277,644 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1134.800 LY (347.917 pc) |