Kepler-263 b
Astrophysical Synthesis & Habitability Characterization
Kepler-263 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-263, located approximately 2461.7 light-years (754.75 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0972% across the stellar disk), this world measures 2.67 Earth radii and has a measured mass of 7.61 Earth masses. Combining its mass and radius yields a mean bulk density of 2.2 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.07 g⊕ (10.49 m/s²), and an escape velocity of 18.9 km/s.
In its orbital architecture around Kepler-263, Kepler-263 b completes one full revolution every 16.568 Earth days at a semi-major axis of 0.12 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 78.8 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 548 K (+275°C / +527°F) and receiving 24.31 S⊕ (~33,083 W/m²), Kepler-263 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-263 is classified as a stellar host with an effective photospheric temperature of 5,265 K, a radius of 0.785 R☉, a mass of 0.793 M☉, an estimated bolometric luminosity of 0.425 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.24 Gyr and a metallicity of [Fe/H] = -0.031 dex (near-solar heavy-element abundance). From Earth, Kepler-263 shines at apparent V-band magnitude 15.435 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-263 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-263 b sharing its stellar neighborhood alongside Kepler-263 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-263 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,265 K |
| Stellar Radius | 0.7850 R☉ |
| Stellar Mass | 0.7930 M☉ |
| Bolometric Luminosity | 0.425 L☉ |
| Metallicity [Fe/H] | -0.031 dex |
| Stellar Age | 2.240 Gyr |
| Apparent Magnitude | V: 15.435 · G: 15.417 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.120000 AU |
| Orbital Period | 16.568 days |
| Mean Orbital Velocity | 78.8 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.6900° |
| Mean Bulk Density | 2.2 g/cm³ (18.9 km/s vesc) |
| Insolation Flux | 24.3080 S⊕ (~33,083 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2461.700 LY (754.747 pc) |