Kepler-1402 b
Astrophysical Synthesis & Habitability Characterization
Kepler-1402 b is a confirmed sub-earth exoplanet orbiting the star Kepler-1402, located approximately 4871.6 light-years (1493.64 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 0.76 Earth radii and has a measured mass of 0.363 Earth masses. Combining its mass and radius yields a mean bulk density of 4.56 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 0.63 g⊕ (6.18 m/s²), and an escape velocity of 7.7 km/s.
In its orbital architecture around Kepler-1402, Kepler-1402 b completes one full revolution every 2.034 Earth days at a semi-major axis of 0.0322 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 172.2 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 1789 K (+1516°C / +2761°F) and receiving 2,491.12 S⊕ (~3,390,413 W/m²), Kepler-1402 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1402 is classified as a stellar host with an effective photospheric temperature of 5,416 K, a radius of 0.87 R☉, a mass of 0.9 M☉, an estimated bolometric luminosity of 0.584 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.57 Gyr and a metallicity of [Fe/H] = 0.03 dex (near-solar heavy-element abundance). From Earth, Kepler-1402 shines at apparent V-band magnitude 14.78 (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-1402 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,416 K |
| Stellar Radius | 0.8700 R☉ |
| Stellar Mass | 0.9000 M☉ |
| Bolometric Luminosity | 0.584 L☉ |
| Metallicity [Fe/H] | 0.030 dex |
| Stellar Age | 4.570 Gyr |
| Apparent Magnitude | V: 14.780 · G: 14.608 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.032200 AU |
| Orbital Period | 2.034 days |
| Mean Orbital Velocity | 172.2 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 87.2400° |
| Mean Bulk Density | 4.56 g/cm³ (7.7 km/s vesc) |
| Insolation Flux | 2491.1190 S⊕ (~3,390,413 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 4871.600 LY (1493.640 pc) |