Kepler-310 d
Astrophysical Synthesis & Habitability Characterization
Kepler-310 d is a confirmed sub-neptune exoplanet orbiting the star Kepler-310, located approximately 1964.3 light-years (602.27 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0668% across the stellar disk), this world measures 2.47 Earth radii and has a measured mass of 7 Earth masses. Combining its mass and radius yields a mean bulk density of 2.56 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.15 g⊕ (11.28 m/s²), and an escape velocity of 18.8 km/s.
In its orbital architecture around Kepler-310, Kepler-310 d completes one full revolution every 92.876 Earth days at a semi-major axis of 0.392 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 45.9 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 353 K (+80°C / +176°F) and receiving 3.66 S⊕ (~4,987 W/m²), Kepler-310 d orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-310 is classified as a stellar host with an effective photospheric temperature of 5,797 K, a radius of 0.876 R☉, a mass of 0.854 M☉, an estimated bolometric luminosity of 0.778 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.9 Gyr and a metallicity of [Fe/H] = -0.12 dex (metal-poor relative to the Sun). From Earth, Kepler-310 shines at apparent V-band magnitude 14.376 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-310 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-310 d sharing its stellar neighborhood alongside Kepler-310 b, Kepler-310 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-310 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,797 K |
| Stellar Radius | 0.8760 R☉ |
| Stellar Mass | 0.8540 M☉ |
| Bolometric Luminosity | 0.778 L☉ |
| Metallicity [Fe/H] | -0.120 dex |
| Stellar Age | 1.900 Gyr |
| Apparent Magnitude | V: 14.376 · G: 14.265 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.392000 AU |
| Orbital Period | 92.876 days |
| Mean Orbital Velocity | 45.9 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.8200° |
| Mean Bulk Density | 2.56 g/cm³ (18.8 km/s vesc) |
| Insolation Flux | 3.6640 S⊕ (~4,987 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1964.300 LY (602.268 pc) |