KOI-351 e
Astrophysical Synthesis & Habitability Characterization
KOI-351 e is a confirmed sub-neptune exoplanet orbiting the star KOI-351, located approximately 2766.6 light-years (848.25 parsecs) from the Solar System. First announced in 2013 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0413% across the stellar disk), this world measures 2.66 Earth radii and has a measured mass of 7.56 Earth masses. Combining its mass and radius yields a mean bulk density of 2.21 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.07 g⊕ (10.49 m/s²), and an escape velocity of 18.9 km/s.
In its orbital architecture around KOI-351, KOI-351 e completes one full revolution every 91.939 Earth days at a semi-major axis of 0.42 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 49.7 km/s (compared to Earth's 29.8 km/s). The orbit is modeled as circular (e = 0.00), maintaining a constant stellar distance throughout its year.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 450 K (+177°C / +351°F) and receiving 10.23 S⊕ (~13,920 W/m²), KOI-351 e orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star KOI-351 is classified as a stellar host with an effective photospheric temperature of 6,080 K, a radius of 1.2 R☉, a mass of 1.2 M☉, an estimated bolometric luminosity of 1.765 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.53 Gyr and a metallicity of [Fe/H] = -0.12 dex (metal-poor relative to the Sun). From Earth, KOI-351 shines at apparent V-band magnitude 13.883 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The KOI-351 system is a multi-planet architecture hosting 8 confirmed worlds, with KOI-351 e sharing its stellar neighborhood alongside KOI-351 b, KOI-351 c, Kepler-90 i, KOI-351 d, KOI-351 f, KOI-351 g, KOI-351 h.
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: Kepler · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | KOI-351 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,080 K |
| Stellar Radius | 1.2000 R☉ |
| Stellar Mass | 1.2000 M☉ |
| Bolometric Luminosity | 1.765 L☉ |
| Metallicity [Fe/H] | -0.120 dex |
| Stellar Age | 0.530 Gyr |
| Apparent Magnitude | V: 13.883 · G: 13.740 |
| System Architecture | 1 Star, 8 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.420000 AU |
| Orbital Period | 91.939 days |
| Mean Orbital Velocity | 49.7 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.7900° |
| Mean Bulk Density | 2.21 g/cm³ (18.9 km/s vesc) |
| Insolation Flux | 10.2280 S⊕ (~13,920 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2766.600 LY (848.254 pc) |