Kepler-219 b
Astrophysical Synthesis & Habitability Characterization
Kepler-219 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-219, located approximately 2567.1 light-years (787.07 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0329% across the stellar disk), this world measures 2.95 Earth radii and has a measured mass of 9.01 Earth masses. Combining its mass and radius yields a mean bulk density of 1.94 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.04 g⊕ (10.2 m/s²), and an escape velocity of 19.5 km/s.
In its orbital architecture around Kepler-219, Kepler-219 b completes one full revolution every 4.586 Earth days at a semi-major axis of 0.057 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 135.2 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 1307 K (+1034°C / +1893°F) and receiving 456.73 S⊕ (~621,612 W/m²), Kepler-219 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-219 is classified as a stellar host with an effective photospheric temperature of 5,786 K, a radius of 1.491 R☉, a mass of 1.164 M☉, an estimated bolometric luminosity of 2.235 L☉. Stellar evolution modeling indicates an estimated stellar age of 4 Gyr and a metallicity of [Fe/H] = 0.36 dex (metal-rich relative to the Sun). From Earth, Kepler-219 shines at apparent V-band magnitude 13.823 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-219 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-219 b sharing its stellar neighborhood alongside Kepler-219 c, Kepler-219 d.
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-219 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,786 K |
| Stellar Radius | 1.4910 R☉ |
| Stellar Mass | 1.1640 M☉ |
| Bolometric Luminosity | 2.235 L☉ |
| Metallicity [Fe/H] | 0.360 dex |
| Stellar Age | 4.000 Gyr |
| Apparent Magnitude | V: 13.823 · G: 13.718 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.057000 AU |
| Orbital Period | 4.586 days |
| Mean Orbital Velocity | 135.2 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 82.3800° |
| Mean Bulk Density | 1.94 g/cm³ (19.5 km/s vesc) |
| Insolation Flux | 456.7320 S⊕ (~621,612 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2567.100 LY (787.070 pc) |