Kepler-1909 b
Astrophysical Synthesis & Habitability Characterization
Kepler-1909 b is a confirmed terrestrial exoplanet orbiting the star Kepler-1909, located approximately 2490.7 light-years (763.66 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0214% across the stellar disk), this world measures 1.092 Earth radii and has a measured mass of 1.33 Earth masses. Combining its mass and radius yields a mean bulk density of 5.63 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.12 g⊕ (10.98 m/s²), and an escape velocity of 12.3 km/s.
In its orbital architecture around Kepler-1909, Kepler-1909 b completes one full revolution every 2.392 Earth days at a semi-major axis of 0.0306 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 139.2 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 1031 K (+758°C / +1396°F) and receiving 266.01 S⊕ (~362,040 W/m²), Kepler-1909 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1909 is classified as a stellar host with an effective photospheric temperature of 4,935 K, a radius of 0.685 R☉, a mass of 0.663 M☉, an estimated bolometric luminosity of 0.25 L☉. Stellar evolution modeling indicates an estimated stellar age of 13.9 Gyr and a metallicity of [Fe/H] = -0.42 dex (metal-poor relative to the Sun). From Earth, Kepler-1909 shines at apparent V-band magnitude 15.933 (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-1909 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,935 K |
| Stellar Radius | 0.6850 R☉ |
| Stellar Mass | 0.6630 M☉ |
| Bolometric Luminosity | 0.25 L☉ |
| Metallicity [Fe/H] | -0.420 dex |
| Stellar Age | 13.900 Gyr |
| Apparent Magnitude | V: 15.933 · G: 15.791 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.030600 AU |
| Orbital Period | 2.392 days |
| Mean Orbital Velocity | 139.2 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.1500° |
| Mean Bulk Density | 5.63 g/cm³ (12.3 km/s vesc) |
| Insolation Flux | 266.0100 S⊕ (~362,040 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2490.700 LY (763.662 pc) |