Kepler-1254 d
Astrophysical Synthesis & Habitability Characterization
Kepler-1254 d is a confirmed super-earth exoplanet orbiting the star Kepler-1254, located approximately 2031.4 light-years (622.82 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0256% across the stellar disk), this world measures 1.31 Earth radii and has a measured mass of 2.27 Earth masses. Combining its mass and radius yields a mean bulk density of 5.57 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.32 g⊕ (12.94 m/s²), and an escape velocity of 14.7 km/s.
In its orbital architecture around Kepler-1254, Kepler-1254 d completes one full revolution every 5.727 Earth days at a semi-major axis of 0.0575 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 109.2 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 794 K (+521°C / +970°F) and receiving 71.31 S⊕ (~97,053 W/m²), Kepler-1254 d orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1254 is classified as a stellar host with an effective photospheric temperature of 4,985 K, a radius of 0.75 R☉, a mass of 0.78 M☉, an estimated bolometric luminosity of 0.312 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.62 Gyr and a metallicity of [Fe/H] = -0.1 dex (near-solar heavy-element abundance). From Earth, Kepler-1254 shines at apparent V-band magnitude 15.541 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-1254 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-1254 d sharing its stellar neighborhood alongside Kepler-1254 c, Kepler-1254 b.
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-1254 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,985 K |
| Stellar Radius | 0.7500 R☉ |
| Stellar Mass | 0.7800 M☉ |
| Bolometric Luminosity | 0.312 L☉ |
| Metallicity [Fe/H] | -0.100 dex |
| Stellar Age | 5.620 Gyr |
| Apparent Magnitude | V: 15.541 · G: 15.302 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.057500 AU |
| Orbital Period | 5.727 days |
| Mean Orbital Velocity | 109.2 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.5700° |
| Mean Bulk Density | 5.57 g/cm³ (14.7 km/s vesc) |
| Insolation Flux | 71.3100 S⊕ (~97,053 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2031.400 LY (622.818 pc) |