K2-64 b
Astrophysical Synthesis & Habitability Characterization
K2-64 b is a confirmed sub-neptune exoplanet orbiting the star K2-64, located approximately 1630.4 light-years (499.89 parsecs) from the Solar System. First announced in 2016 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.0683% across the stellar disk), this world measures 2.07 Earth radii and has a measured mass of 4.94 Earth masses. Combining its mass and radius yields a mean bulk density of 3.07 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.15 g⊕ (11.28 m/s²), and an escape velocity of 17.3 km/s.
In its orbital architecture around K2-64, K2-64 b completes one full revolution every 6.53 Earth days at a semi-major axis of 0.0619 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 103.1 km/s (compared to Earth's 29.8 km/s).
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 877 K (+604°C / +1119°F) and receiving 98.00 S⊕ (~133,378 W/m²), K2-64 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star K2-64 is classified as a stellar host with an effective photospheric temperature of 5,312 K, a radius of 0.726 R☉, a mass of 0.741 M☉, an estimated bolometric luminosity of 0.377 L☉. From Earth, K2-64 shines at apparent V-band magnitude 14.132 (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 | K2-64 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,312 K |
| Stellar Radius | 0.7260 R☉ |
| Stellar Mass | 0.7410 M☉ |
| Bolometric Luminosity | 0.377 L☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | — |
| Apparent Magnitude | V: 14.132 · G: 13.915 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.061900 AU |
| Orbital Period | 6.53 days |
| Mean Orbital Velocity | 103.1 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 3.07 g/cm³ (17.3 km/s vesc) |
| Insolation Flux | 98.0000 S⊕ (~133,378 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1630.400 LY (499.891 pc) |