Kepler-351 b
Astrophysical Synthesis & Habitability Characterization
Kepler-351 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-351, located approximately 3535.2 light-years (1083.91 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.1079% across the stellar disk), this world measures 3.06 Earth radii (0.27 Jupiter radii) and has a measured mass of 4.8 Earth masses. Combining its mass and radius yields a mean bulk density of 0.92 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.51 g⊕ (5 m/s²), and an escape velocity of 14 km/s.
In its orbital architecture around Kepler-351, Kepler-351 b completes one full revolution every 37.055 Earth days at a semi-major axis of 0.214 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 62.8 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 498 K (+225°C / +437°F) and receiving 11.98 S⊕ (~16,309 W/m²), Kepler-351 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-351 is classified as a stellar host with an effective photospheric temperature of 5,643 K, a radius of 0.854 R☉, a mass of 0.81 M☉, an estimated bolometric luminosity of 0.664 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.9 Gyr and a metallicity of [Fe/H] = -0.16 dex (metal-poor relative to the Sun). From Earth, Kepler-351 shines at apparent V-band magnitude 16.229 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-351 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-351 b sharing its stellar neighborhood alongside Kepler-351 c, Kepler-351 d.
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 | Kepler-351 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,643 K |
| Stellar Radius | 0.8540 R☉ |
| Stellar Mass | 0.8100 M☉ |
| Bolometric Luminosity | 0.664 L☉ |
| Metallicity [Fe/H] | -0.160 dex |
| Stellar Age | 2.900 Gyr |
| Apparent Magnitude | V: 16.229 · G: 15.967 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.214000 AU |
| Orbital Period | 37.055 days |
| Mean Orbital Velocity | 62.8 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.1900° |
| Mean Bulk Density | 0.92 g/cm³ (14 km/s vesc) |
| Insolation Flux | 11.9830 S⊕ (~16,309 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 3535.200 LY (1083.910 pc) |