K2-417 b
Astrophysical Synthesis & Habitability Characterization
K2-417 b is a confirmed sub-neptune exoplanet orbiting the star K2-417, located approximately 306.7 light-years (94.04 parsecs) from the Solar System. First announced in 2023 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.276% across the stellar disk), this world measures 3.31 Earth radii (0.3 Jupiter radii) and has a measured mass of 699.222 Earth masses (2.2 Jupiter masses). Combining its mass and radius yields a mean bulk density of 106.32 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 63.82 g⊕ (625.86 m/s²), and an escape velocity of 162.6 km/s.
In its orbital architecture around K2-417, K2-417 b completes one full revolution every 6.535 Earth days at a semi-major axis of 0.063 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 104.9 km/s (compared to Earth's 29.8 km/s).
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 558 K (+285°C / +545°F) and receiving 15.82 S⊕ (~21,535 W/m²), K2-417 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star K2-417 is classified as a low-mass red dwarf of spectral type M V with an effective photospheric temperature of 3,861 K, a radius of 0.5776 R☉, a mass of 0.569 M☉, an estimated bolometric luminosity of 0.067 L☉. From Earth, K2-417 shines at apparent V-band magnitude 13.909 (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 | K2-417 |
| Spectral Type | M V |
| Effective Temp (Teff) | 3,861 K |
| Stellar Radius | 0.5776 R☉ |
| Stellar Mass | 0.5690 M☉ |
| Bolometric Luminosity | 0.067 L☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | — |
| Apparent Magnitude | V: 13.909 · G: 13.153 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.063000 AU |
| Orbital Period | 6.535 days |
| Mean Orbital Velocity | 104.9 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 89.0000° |
| Mean Bulk Density | 106.32 g/cm³ (162.6 km/s vesc) |
| Insolation Flux | 15.8226 S⊕ (~21,535 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 306.700 LY (94.042 pc) |