Kepler-319 d
Astrophysical Synthesis & Habitability Characterization
Kepler-319 d is a confirmed sub-neptune exoplanet orbiting the star Kepler-319, located approximately 1642 light-years (503.44 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0541% across the stellar disk), this world measures 2.29 Earth radii and has a measured mass of 5.86 Earth masses. Combining its mass and radius yields a mean bulk density of 2.69 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.12 g⊕ (10.98 m/s²), and an escape velocity of 17.9 km/s.
In its orbital architecture around Kepler-319, Kepler-319 d completes one full revolution every 31.782 Earth days at a semi-major axis of 0.191 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 65.4 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 528 K (+255°C / +491°F) and receiving 17.96 S⊕ (~24,446 W/m²), Kepler-319 d orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-319 is classified as a stellar host with an effective photospheric temperature of 5,526 K, a radius of 0.903 R☉, a mass of 0.933 M☉, an estimated bolometric luminosity of 0.682 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.07 Gyr and a metallicity of [Fe/H] = 0.06 dex (metal-rich relative to the Sun). From Earth, Kepler-319 shines at apparent V-band magnitude 13.926 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-319 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-319 d sharing its stellar neighborhood alongside Kepler-319 b, Kepler-319 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-319 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,526 K |
| Stellar Radius | 0.9030 R☉ |
| Stellar Mass | 0.9330 M☉ |
| Bolometric Luminosity | 0.682 L☉ |
| Metallicity [Fe/H] | 0.060 dex |
| Stellar Age | 1.070 Gyr |
| Apparent Magnitude | V: 13.926 · G: 13.791 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.191000 AU |
| Orbital Period | 31.782 days |
| Mean Orbital Velocity | 65.4 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.8500° |
| Mean Bulk Density | 2.69 g/cm³ (17.9 km/s vesc) |
| Insolation Flux | 17.9620 S⊕ (~24,446 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1642.000 LY (503.436 pc) |