K2-74 b
Astrophysical Synthesis & Habitability Characterization
K2-74 b is a confirmed sub-neptune exoplanet orbiting the star K2-74, located approximately 1232.3 light-years (377.82 parsecs) from the Solar System. First announced in 2016 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.0467% across the stellar disk), this world measures 2.31 Earth radii and has a measured mass of 5.95 Earth masses. Combining its mass and radius yields a mean bulk density of 2.66 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.12 g⊕ (10.98 m/s²), and an escape velocity of 18 km/s.
In its orbital architecture around K2-74, K2-74 b completes one full revolution every 19.567 Earth days at a semi-major axis of 0.1402 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 78 km/s (compared to Earth's 29.8 km/s).
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 773 K (+500°C / +932°F) and receiving 59.10 S⊕ (~80,435 W/m²), K2-74 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star K2-74 is classified as a stellar host with an effective photospheric temperature of 6,060 K, a radius of 0.98 R☉, a mass of 0.96 M☉, an estimated bolometric luminosity of 1.162 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.21 dex (metal-poor relative to the Sun). From Earth, K2-74 shines at apparent V-band magnitude 12.715 (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 | K2-74 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,060 K |
| Stellar Radius | 0.9800 R☉ |
| Stellar Mass | 0.9600 M☉ |
| Bolometric Luminosity | 1.162 L☉ |
| Metallicity [Fe/H] | -0.210 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 12.715 · G: 12.436 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.140200 AU |
| Orbital Period | 19.567 days |
| Mean Orbital Velocity | 78 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 88.9199° |
| Mean Bulk Density | 2.66 g/cm³ (18 km/s vesc) |
| Insolation Flux | 59.1000 S⊕ (~80,435 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1232.300 LY (377.822 pc) |