Kepler-350 d
Astrophysical Synthesis & Habitability Characterization
Kepler-350 d is a confirmed sub-neptune exoplanet orbiting the star Kepler-350, located approximately 3120.9 light-years (956.86 parsecs) from the Solar System. First announced in 2013 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0422% across the stellar disk), this world measures 2.8 Earth radii and has a measured mass of 14.9 Earth masses. Combining its mass and radius yields a mean bulk density of 3.74 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.9 g⊕ (18.63 m/s²), and an escape velocity of 25.8 km/s.
In its orbital architecture around Kepler-350, Kepler-350 d completes one full revolution every 26.136 Earth days at a semi-major axis of 0.1786 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 74.3 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 782 K (+509°C / +948°F) and receiving 83.24 S⊕ (~113,286 W/m²), Kepler-350 d orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-350 is classified as a stellar host with an effective photospheric temperature of 6,492 K, a radius of 1.25 R☉, a mass of 1 M☉, an estimated bolometric luminosity of 2.49 L☉. Stellar evolution modeling indicates an estimated stellar age of 4 Gyr and a metallicity of [Fe/H] = 0.041 dex (near-solar heavy-element abundance). From Earth, Kepler-350 shines at apparent V-band magnitude 13.965 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-350 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-350 d sharing its stellar neighborhood alongside Kepler-350 b, Kepler-350 c.
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-350 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,492 K |
| Stellar Radius | 1.2500 R☉ |
| Stellar Mass | 1.0000 M☉ |
| Bolometric Luminosity | 2.49 L☉ |
| Metallicity [Fe/H] | 0.041 dex |
| Stellar Age | 4.000 Gyr |
| Apparent Magnitude | V: 13.965 · G: 13.761 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.178600 AU |
| Orbital Period | 26.136 days |
| Mean Orbital Velocity | 74.3 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.6500° |
| Mean Bulk Density | 3.74 g/cm³ (25.8 km/s vesc) |
| Insolation Flux | 83.2370 S⊕ (~113,286 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 3120.900 LY (956.859 pc) |