K2-268 c
Astrophysical Synthesis & Habitability Characterization
K2-268 c is a confirmed sub-neptune exoplanet orbiting the star K2-268, located approximately 1069.1 light-years (327.78 parsecs) from the Solar System. First announced in 2018 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.1% across the stellar disk), this world measures 2.69 Earth radii and has a measured mass of 7.7 Earth masses. Combining its mass and radius yields a mean bulk density of 2.18 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.06 g⊕ (10.4 m/s²), and an escape velocity of 18.9 km/s.
In its orbital architecture around K2-268, K2-268 c completes one full revolution every 9.328 Earth days at a semi-major axis of 0.0819 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 95.5 km/s (compared to Earth's 29.8 km/s).
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 696 K (+423°C / +793°F) and receiving 55.46 S⊕ (~75,486 W/m²), K2-268 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star K2-268 is classified as a stellar host with an effective photospheric temperature of 5,106 K, a radius of 0.78 R☉, a mass of 0.84 M☉, an estimated bolometric luminosity of 0.371 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.03 dex (near-solar heavy-element abundance). From Earth, K2-268 shines at apparent V-band magnitude 13.848 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The K2-268 system is a multi-planet architecture hosting 5 confirmed worlds, with K2-268 c sharing its stellar neighborhood alongside K2-268 b, K2-268 d, K2-268 e, K2-268 f.
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 | K2-268 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,106 K |
| Stellar Radius | 0.7800 R☉ |
| Stellar Mass | 0.8400 M☉ |
| Bolometric Luminosity | 0.371 L☉ |
| Metallicity [Fe/H] | 0.030 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 13.848 · G: 13.563 |
| System Architecture | 1 Star, 5 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.081900 AU |
| Orbital Period | 9.328 days |
| Mean Orbital Velocity | 95.5 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 88.7100° |
| Mean Bulk Density | 2.18 g/cm³ (18.9 km/s vesc) |
| Insolation Flux | 55.4636 S⊕ (~75,486 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1069.100 LY (327.783 pc) |