Kepler-1130 d
Astrophysical Synthesis & Habitability Characterization
Kepler-1130 d is a confirmed sub-earth exoplanet orbiting the star Kepler-1130, located approximately 813.2 light-years (249.34 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0049% across the stellar disk), this world measures 0.645 Earth radii and has a measured mass of 0.202 Earth masses. Combining its mass and radius yields a mean bulk density of 4.15 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 0.49 g⊕ (4.81 m/s²), and an escape velocity of 6.3 km/s.
In its orbital architecture around Kepler-1130, Kepler-1130 d completes one full revolution every 4.272 Earth days at a semi-major axis of 0.05068 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 129.1 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 981 K (+708°C / +1306°F) and receiving 221.40 S⊕ (~301,325 W/m²), Kepler-1130 d orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1130 is classified as a stellar host with an effective photospheric temperature of 5,450 K, a radius of 0.842 R☉, a mass of 0.944 M☉, an estimated bolometric luminosity of 0.561 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.58 Gyr and a metallicity of [Fe/H] = 0.1 dex (metal-rich relative to the Sun). From Earth, Kepler-1130 shines at apparent V-band magnitude 12.509 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-1130 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-1130 d sharing its stellar neighborhood alongside Kepler-1130 c, Kepler-1130 b.
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-1130 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,450 K |
| Stellar Radius | 0.8420 R☉ |
| Stellar Mass | 0.9440 M☉ |
| Bolometric Luminosity | 0.561 L☉ |
| Metallicity [Fe/H] | 0.100 dex |
| Stellar Age | 1.580 Gyr |
| Apparent Magnitude | V: 12.509 · G: 12.396 |
| System Architecture | 2 Stars, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.050680 AU |
| Orbital Period | 4.272 days |
| Mean Orbital Velocity | 129.1 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 85.9500° |
| Mean Bulk Density | 4.15 g/cm³ (6.3 km/s vesc) |
| Insolation Flux | 221.4000 S⊕ (~301,325 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 813.200 LY (249.343 pc) |