Kepler-403 b
Astrophysical Synthesis & Habitability Characterization
Kepler-403 b is a confirmed terrestrial exoplanet orbiting the star Kepler-403, located approximately 2740.6 light-years (840.27 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0074% across the stellar disk), this world measures 1.25 Earth radii and has a measured mass of 2.1 Earth masses. Combining its mass and radius yields a mean bulk density of 5.93 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.34 g⊕ (13.14 m/s²), and an escape velocity of 14.5 km/s.
In its orbital architecture around Kepler-403, Kepler-403 b completes one full revolution every 7.031 Earth days at a semi-major axis of 0.076 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 117.6 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 1194 K (+921°C / +1690°F) and receiving 689.46 S⊕ (~938,351 W/m²), Kepler-403 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-403 is classified as a stellar host with an effective photospheric temperature of 6,090 K, a radius of 1.329 R☉, a mass of 1.299 M☉, an estimated bolometric luminosity of 2.18 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.09 Gyr and a metallicity of [Fe/H] = 0.079 dex (metal-rich relative to the Sun). From Earth, Kepler-403 shines at apparent V-band magnitude 12.818 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-403 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-403 b sharing its stellar neighborhood alongside Kepler-403 d, Kepler-403 c.
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-403 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,090 K |
| Stellar Radius | 1.3290 R☉ |
| Stellar Mass | 1.2990 M☉ |
| Bolometric Luminosity | 2.18 L☉ |
| Metallicity [Fe/H] | 0.079 dex |
| Stellar Age | 3.090 Gyr |
| Apparent Magnitude | V: 12.818 · G: 12.760 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.076000 AU |
| Orbital Period | 7.031 days |
| Mean Orbital Velocity | 117.6 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.9100° |
| Mean Bulk Density | 5.93 g/cm³ (14.5 km/s vesc) |
| Insolation Flux | 689.4570 S⊕ (~938,351 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2740.600 LY (840.269 pc) |