Kepler-359 d
Astrophysical Synthesis & Habitability Characterization
Kepler-359 d is a confirmed sub-neptune exoplanet orbiting the star Kepler-359, located approximately 4707.1 light-years (1443.21 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.1146% across the stellar disk), this world measures 4.01 Earth radii (0.36 Jupiter radii) and has a measured mass of 2.7 Earth masses. Combining its mass and radius yields a mean bulk density of 0.23 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.17 g⊕ (1.67 m/s²), and an escape velocity of 9.2 km/s.
In its orbital architecture around Kepler-359, Kepler-359 d completes one full revolution every 77.096 Earth days at a semi-major axis of 0.372 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 52.5 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 464 K (+191°C / +376°F) and receiving 5.50 S⊕ (~7,486 W/m²), Kepler-359 d orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-359 is classified as a stellar host with an effective photospheric temperature of 6,248 K, a radius of 1.086 R☉, a mass of 0.827 M☉, an estimated bolometric luminosity of 1.613 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.02 Gyr and a metallicity of [Fe/H] = -0.29 dex (metal-poor relative to the Sun). From Earth, Kepler-359 shines at apparent V-band magnitude 15.805 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-359 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-359 d sharing its stellar neighborhood alongside Kepler-359 b, Kepler-359 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-359 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,248 K |
| Stellar Radius | 1.0860 R☉ |
| Stellar Mass | 0.8270 M☉ |
| Bolometric Luminosity | 1.613 L☉ |
| Metallicity [Fe/H] | -0.290 dex |
| Stellar Age | 3.020 Gyr |
| Apparent Magnitude | V: 15.805 · G: 15.881 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.372000 AU |
| Orbital Period | 77.096 days |
| Mean Orbital Velocity | 52.5 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.0000° |
| Mean Bulk Density | 0.23 g/cm³ (9.2 km/s vesc) |
| Insolation Flux | 5.5000 S⊕ (~7,486 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 4707.100 LY (1443.210 pc) |