K2-345 b
Astrophysical Synthesis & Habitability Characterization
K2-345 b is a confirmed sub-neptune exoplanet orbiting the star K2-345, located approximately 529.7 light-years (162.41 parsecs) from the Solar System. First announced in 2021 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.1384% across the stellar disk), this world measures 2.11 Earth radii and has a measured mass of 5.1 Earth masses. Combining its mass and radius yields a mean bulk density of 2.99 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 17.4 km/s.
In its orbital architecture around K2-345, K2-345 b completes one full revolution every 10.367 Earth days.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 437 K (+164°C / +327°F), K2-345 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star K2-345 is classified as a stellar host with an effective photospheric temperature of 3,779 K, a radius of 0.52 R☉, a mass of 0.56 M☉, an estimated bolometric luminosity of 0.049 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.26 dex (metal-rich relative to the Sun). From Earth, K2-345 shines at apparent V-band magnitude 15.72 (faint and requiring research-grade or CCD telescopic photometry) in the Northern 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 | K2-345 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 3,779 K |
| Stellar Radius | 0.5200 R☉ |
| Stellar Mass | 0.5600 M☉ |
| Bolometric Luminosity | 0.049 L☉ |
| Metallicity [Fe/H] | 0.260 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 15.720 · G: 14.695 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | — |
| Orbital Period | 10.367 days |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 2.99 g/cm³ (17.4 km/s vesc) |
| Insolation Flux | — |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 529.700 LY (162.408 pc) |