Kepler-54 b
Astrophysical Synthesis & Habitability Characterization
Kepler-54 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-54, located approximately 886.2 light-years (271.7 parsecs) from the Solar System. First announced in 2012 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.1483% across the stellar disk), this world measures 2.1 Earth radii and has a measured mass of 0.98 Earth masses. Combining its mass and radius yields a mean bulk density of 0.58 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.22 g⊕ (2.16 m/s²), and an escape velocity of 7.6 km/s.
In its orbital architecture around Kepler-54, Kepler-54 b completes one full revolution every 8.011 Earth days at a semi-major axis of 0.0619 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 84.1 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.022 (ranging from 0.0605 AU at periapsis to 0.0633 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 453 K (+180°C / +356°F) and receiving 12.36 S⊕ (~16,818 W/m²), Kepler-54 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-54 is classified as a low-mass red dwarf of spectral type M1 V with an effective photospheric temperature of 3,705 K, a radius of 0.5 R☉, a mass of 0.51 M☉, an estimated bolometric luminosity of 0.042 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.83 Gyr and a metallicity of [Fe/H] = -0.27 dex (metal-poor relative to the Sun). From Earth, Kepler-54 shines at apparent V-band magnitude 16.282 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-54 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-54 b sharing its stellar neighborhood alongside Kepler-54 c, Kepler-54 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-54 |
| Spectral Type | M1 V |
| Effective Temp (Teff) | 3,705 K |
| Stellar Radius | 0.5000 R☉ |
| Stellar Mass | 0.5100 M☉ |
| Bolometric Luminosity | 0.042 L☉ |
| Metallicity [Fe/H] | -0.270 dex |
| Stellar Age | 4.830 Gyr |
| Apparent Magnitude | V: 16.282 · G: 15.813 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.061900 AU |
| Orbital Period | 8.011 days |
| Mean Orbital Velocity | 84.1 km/s |
| Orbital Eccentricity (e) | 0.02200 |
| Orbital Inclination (i) | 89.5900° |
| Mean Bulk Density | 0.58 g/cm³ (7.6 km/s vesc) |
| Insolation Flux | 12.3570 S⊕ (~16,818 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 886.200 LY (271.701 pc) |