Kepler-1390 b
Astrophysical Synthesis & Habitability Characterization
Kepler-1390 b is a confirmed terrestrial exoplanet orbiting the star Kepler-1390, located approximately 2359.5 light-years (723.43 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0122% across the stellar disk), this world measures 1.18 Earth radii and has a measured mass of 1.76 Earth masses. Combining its mass and radius yields a mean bulk density of 5.91 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.26 g⊕ (12.36 m/s²), and an escape velocity of 13.7 km/s.
In its orbital architecture around Kepler-1390, Kepler-1390 b completes one full revolution every 6.48 Earth days at a semi-major axis of 0.0662 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 111.1 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 934 K (+661°C / +1222°F) and receiving 171.13 S⊕ (~232,912 W/m²), Kepler-1390 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1390 is classified as a stellar host with an effective photospheric temperature of 5,753 K, a radius of 0.98 R☉, a mass of 0.98 M☉, an estimated bolometric luminosity of 0.944 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.47 Gyr and a metallicity of [Fe/H] = -0.01 dex (near-solar heavy-element abundance). From Earth, Kepler-1390 shines at apparent V-band magnitude 14.558 (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-1390 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,753 K |
| Stellar Radius | 0.9800 R☉ |
| Stellar Mass | 0.9800 M☉ |
| Bolometric Luminosity | 0.944 L☉ |
| Metallicity [Fe/H] | -0.010 dex |
| Stellar Age | 4.470 Gyr |
| Apparent Magnitude | V: 14.558 · G: 14.402 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.066200 AU |
| Orbital Period | 6.48 days |
| Mean Orbital Velocity | 111.1 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 86.1200° |
| Mean Bulk Density | 5.91 g/cm³ (13.7 km/s vesc) |
| Insolation Flux | 171.1330 S⊕ (~232,912 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2359.500 LY (723.431 pc) |