Kepler-254 b
Astrophysical Synthesis & Habitability Characterization
Kepler-254 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-254, located approximately 4531.9 light-years (1389.48 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.152% across the stellar disk), this world measures 3.87 Earth radii (0.35 Jupiter radii) and has a measured mass of 14.3 Earth masses. Combining its mass and radius yields a mean bulk density of 1.36 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.95 g⊕ (9.32 m/s²), and an escape velocity of 21.5 km/s.
In its orbital architecture around Kepler-254, Kepler-254 b completes one full revolution every 5.827 Earth days at a semi-major axis of 0.064 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 119.5 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 1013 K (+740°C / +1364°F) and receiving 184.34 S⊕ (~250,888 W/m²), Kepler-254 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-254 is classified as a stellar host with an effective photospheric temperature of 5,957 K, a radius of 0.91 R☉, a mass of 0.849 M☉, an estimated bolometric luminosity of 0.936 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.3 Gyr and a metallicity of [Fe/H] = -0.13 dex (metal-poor relative to the Sun). From Earth, Kepler-254 shines at apparent V-band magnitude 16.012 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-254 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-254 b sharing its stellar neighborhood alongside Kepler-254 c, Kepler-254 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-254 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,957 K |
| Stellar Radius | 0.9100 R☉ |
| Stellar Mass | 0.8490 M☉ |
| Bolometric Luminosity | 0.936 L☉ |
| Metallicity [Fe/H] | -0.130 dex |
| Stellar Age | 0.300 Gyr |
| Apparent Magnitude | V: 16.012 · G: 15.838 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.064000 AU |
| Orbital Period | 5.827 days |
| Mean Orbital Velocity | 119.5 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.8800° |
| Mean Bulk Density | 1.36 g/cm³ (21.5 km/s vesc) |
| Insolation Flux | 184.3410 S⊕ (~250,888 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 4531.900 LY (1389.480 pc) |