Kepler-1278 b
Astrophysical Synthesis & Habitability Characterization
Kepler-1278 b is a confirmed terrestrial exoplanet orbiting the star Kepler-1278, located approximately 2900.9 light-years (889.43 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0064% across the stellar disk), this world measures 1.01 Earth radii and has a measured mass of 1.01 Earth masses. Combining its mass and radius yields a mean bulk density of 5.41 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 0.99 g⊕ (9.71 m/s²), and an escape velocity of 11.2 km/s.
In its orbital architecture around Kepler-1278, Kepler-1278 b completes one full revolution every 3.239 Earth days at a semi-major axis of 0.04417 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 148.3 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 1213 K (+940°C / +1724°F) and receiving 1,314.67 S⊕ (~1,789,266 W/m²), Kepler-1278 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1278 is classified as a stellar host with an effective photospheric temperature of 6,074 K, a radius of 1.16 R☉, a mass of 1.11 M☉, an estimated bolometric luminosity of 1.643 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.31 Gyr and a metallicity of [Fe/H] = 0.02 dex (near-solar heavy-element abundance). From Earth, Kepler-1278 shines at apparent V-band magnitude 13.782 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.
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-1278 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,074 K |
| Stellar Radius | 1.1600 R☉ |
| Stellar Mass | 1.1100 M☉ |
| Bolometric Luminosity | 1.643 L☉ |
| Metallicity [Fe/H] | 0.020 dex |
| Stellar Age | 3.310 Gyr |
| Apparent Magnitude | V: 13.782 · G: 13.632 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.044170 AU |
| Orbital Period | 3.239 days |
| Mean Orbital Velocity | 148.3 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 87.5400° |
| Mean Bulk Density | 5.41 g/cm³ (11.2 km/s vesc) |
| Insolation Flux | 1314.6700 S⊕ (~1,789,266 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2900.900 LY (889.426 pc) |