Kepler-879 b
Astrophysical Synthesis & Habitability Characterization
Kepler-879 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-879, located approximately 2618 light-years (802.67 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0534% across the stellar disk), this world measures 2.57 Earth radii and has a measured mass of 7.13 Earth masses. Combining its mass and radius yields a mean bulk density of 2.32 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.08 g⊕ (10.59 m/s²), and an escape velocity of 18.6 km/s.
In its orbital architecture around Kepler-879, Kepler-879 b completes one full revolution every 33.386 Earth days at a semi-major axis of 0.2012 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 65.6 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 580 K (+307°C / +585°F) and receiving 29.13 S⊕ (~39,643 W/m²), Kepler-879 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-879 is classified as a solar-type yellow star of spectral type G with an effective photospheric temperature of 5,792 K, a radius of 1.02 R☉, a mass of 1.02 M☉, an estimated bolometric luminosity of 1.051 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.27 Gyr and a metallicity of [Fe/H] = 0.05 dex (near-solar heavy-element abundance). From Earth, Kepler-879 shines at apparent V-band magnitude 14.429 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-879 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-879 b sharing its stellar neighborhood alongside Kepler-879 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-879 |
| Spectral Type | G |
| Effective Temp (Teff) | 5,792 K |
| Stellar Radius | 1.0200 R☉ |
| Stellar Mass | 1.0200 M☉ |
| Bolometric Luminosity | 1.051 L☉ |
| Metallicity [Fe/H] | 0.050 dex |
| Stellar Age | 4.270 Gyr |
| Apparent Magnitude | V: 14.429 · G: 14.238 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.201200 AU |
| Orbital Period | 33.386 days |
| Mean Orbital Velocity | 65.6 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.2600° |
| Mean Bulk Density | 2.32 g/cm³ (18.6 km/s vesc) |
| Insolation Flux | 29.1280 S⊕ (~39,643 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2618.000 LY (802.672 pc) |