K2-279 b
Astrophysical Synthesis & Habitability Characterization
K2-279 b is a confirmed terrestrial exoplanet orbiting the star K2-279, located approximately 596.8 light-years (182.98 parsecs) from the Solar System. First announced in 2018 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.0166% across the stellar disk), this world measures 1.21 Earth radii and has a measured mass of 1.92 Earth masses. Combining its mass and radius yields a mean bulk density of 5.98 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.31 g⊕ (12.85 m/s²), and an escape velocity of 14.1 km/s.
In its orbital architecture around K2-279, K2-279 b completes one full revolution every 7.123 Earth days at a semi-major axis of 0.067 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 102.3 km/s (compared to Earth's 29.8 km/s).
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 879 K (+606°C / +1123°F) and receiving 139.11 S⊕ (~189,323 W/m²), K2-279 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star K2-279 is classified as a stellar host with an effective photospheric temperature of 5,558 K, a radius of 0.86 R☉, a mass of 0.79 M☉, an estimated bolometric luminosity of 0.633 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.37 dex (metal-poor relative to the Sun). From Earth, K2-279 shines at apparent V-band magnitude 11.491 (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 | K2-279 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,558 K |
| Stellar Radius | 0.8600 R☉ |
| Stellar Mass | 0.7900 M☉ |
| Bolometric Luminosity | 0.633 L☉ |
| Metallicity [Fe/H] | -0.370 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 11.491 · G: 11.591 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.067000 AU |
| Orbital Period | 7.123 days |
| Mean Orbital Velocity | 102.3 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 5.98 g/cm³ (14.1 km/s vesc) |
| Insolation Flux | 139.1055 S⊕ (~189,323 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 596.800 LY (182.983 pc) |