Kepler-725 b
Astrophysical Synthesis & Habitability Characterization
Kepler-725 b is a confirmed gas giant exoplanet orbiting the star Kepler-725, located approximately 2473.8 light-years (758.47 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 1.266% across the stellar disk), this world measures 10.8 Earth radii (0.96 Jupiter radii) and has a measured mass of 521.762 Earth masses (1.64 Jupiter masses). Combining its mass and radius yields a mean bulk density of 2.28 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 4.47 g⊕ (43.84 m/s²), and an escape velocity of 77.7 km/s.
In its orbital architecture around Kepler-725, Kepler-725 b completes one full revolution every 39.644 Earth days at a semi-major axis of 0.2238 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 61.4 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.231 carries the world between 0.1721 AU at periapsis and 0.2755 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 514 K (+241°C / +466°F) and receiving 12.10 S⊕ (~16,468 W/m²), Kepler-725 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-725 is classified as a solar-type yellow star of spectral type G with an effective photospheric temperature of 5,395 K, a radius of 0.88 R☉, a mass of 0.95 M☉, an estimated bolometric luminosity of 0.589 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.6 Gyr and a metallicity of [Fe/H] = 0.14 dex (metal-rich relative to the Sun). From Earth, Kepler-725 shines at apparent V-band magnitude 15.145 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-725 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-725 b sharing its stellar neighborhood alongside Kepler-725 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-725 |
| Spectral Type | G |
| Effective Temp (Teff) | 5,395 K |
| Stellar Radius | 0.8800 R☉ |
| Stellar Mass | 0.9500 M☉ |
| Bolometric Luminosity | 0.589 L☉ |
| Metallicity [Fe/H] | 0.140 dex |
| Stellar Age | 1.600 Gyr |
| Apparent Magnitude | V: 15.145 · G: 14.993 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.223800 AU |
| Orbital Period | 39.644 days |
| Mean Orbital Velocity | 61.4 km/s |
| Orbital Eccentricity (e) | 0.23100 |
| Orbital Inclination (i) | 89.8000° |
| Mean Bulk Density | 2.28 g/cm³ (77.7 km/s vesc) |
| Insolation Flux | 12.1000 S⊕ (~16,468 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2473.800 LY (758.469 pc) |