Kepler-369 b
Astrophysical Synthesis & Habitability Characterization
Kepler-369 b is a confirmed terrestrial exoplanet orbiting the star Kepler-369, located approximately 698 light-years (214 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0484% across the stellar disk), this world measures 1.13 Earth radii and has a measured mass of 1.51 Earth masses. Combining its mass and radius yields a mean bulk density of 5.77 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.18 g⊕ (11.57 m/s²), and an escape velocity of 12.9 km/s.
In its orbital architecture around Kepler-369, Kepler-369 b completes one full revolution every 2.733 Earth days at a semi-major axis of 0.03 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 119.4 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 687 K (+414°C / +777°F) and receiving 40.30 S⊕ (~54,841 W/m²), Kepler-369 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-369 is classified as a stellar host with an effective photospheric temperature of 3,591 K, a radius of 0.471 R☉, a mass of 0.5 M☉, an estimated bolometric luminosity of 0.033 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.17 Gyr and a metallicity of [Fe/H] = -0.09 dex (near-solar heavy-element abundance). From Earth, Kepler-369 shines at apparent V-band magnitude 16.429 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-369 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-369 b sharing its stellar neighborhood alongside Kepler-369 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-369 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 3,591 K |
| Stellar Radius | 0.4710 R☉ |
| Stellar Mass | 0.5000 M☉ |
| Bolometric Luminosity | 0.033 L☉ |
| Metallicity [Fe/H] | -0.090 dex |
| Stellar Age | 4.170 Gyr |
| Apparent Magnitude | V: 16.429 · G: 15.668 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.030000 AU |
| Orbital Period | 2.733 days |
| Mean Orbital Velocity | 119.4 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 86.7600° |
| Mean Bulk Density | 5.77 g/cm³ (12.9 km/s vesc) |
| Insolation Flux | 40.2950 S⊕ (~54,841 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 698.000 LY (214.000 pc) |