KOI-94 d
Astrophysical Synthesis & Habitability Characterization
KOI-94 d is a confirmed gas giant exoplanet orbiting the star KOI-94, located approximately 1555.9 light-years (477.05 parsecs) from the Solar System. First announced in 2013 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.4621% across the stellar disk), this world measures 11.27 Earth radii (1.01 Jupiter radii) and has a measured mass of 106 Earth masses (0.33 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.41 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.83 g⊕ (8.14 m/s²), and an escape velocity of 34.3 km/s.
In its orbital architecture around KOI-94, KOI-94 d completes one full revolution every 22.343 Earth days at a semi-major axis of 0.1684 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 82 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.022 (ranging from 0.1647 AU at periapsis to 0.1721 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 806 K (+533°C / +991°F) and receiving 97.12 S⊕ (~132,180 W/m²), KOI-94 d orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star KOI-94 is classified as a stellar host with an effective photospheric temperature of 6,182 K, a radius of 1.52 R☉, a mass of 1.277 M☉, an estimated bolometric luminosity of 3.028 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.16 Gyr and a metallicity of [Fe/H] = 0.023 dex (near-solar heavy-element abundance). From Earth, KOI-94 shines at apparent V-band magnitude 12.314 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The KOI-94 system is a multi-planet architecture hosting 4 confirmed worlds, with KOI-94 d sharing its stellar neighborhood alongside KOI-94 b, KOI-94 c, KOI-94 e.
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 | KOI-94 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,182 K |
| Stellar Radius | 1.5200 R☉ |
| Stellar Mass | 1.2770 M☉ |
| Bolometric Luminosity | 3.028 L☉ |
| Metallicity [Fe/H] | 0.023 dex |
| Stellar Age | 3.160 Gyr |
| Apparent Magnitude | V: 12.314 · G: 12.188 |
| System Architecture | 2 Stars, 4 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.168400 AU |
| Orbital Period | 22.343 days |
| Mean Orbital Velocity | 82 km/s |
| Orbital Eccentricity (e) | 0.02200 |
| Orbital Inclination (i) | 89.8710° |
| Mean Bulk Density | 0.41 g/cm³ (34.3 km/s vesc) |
| Insolation Flux | 97.1200 S⊕ (~132,180 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1555.900 LY (477.052 pc) |