Kepler-1154 c
Astrophysical Synthesis & Habitability Characterization
Kepler-1154 c is a confirmed sub-neptune exoplanet orbiting the star Kepler-1154, located approximately 4762.2 light-years (1460.1 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0229% across the stellar disk), this world measures 2.36 Earth radii and has a measured mass of 6.17 Earth masses. Combining its mass and radius yields a mean bulk density of 2.59 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.11 g⊕ (10.89 m/s²), and an escape velocity of 18.1 km/s.
In its orbital architecture around Kepler-1154, Kepler-1154 c completes one full revolution every 8.458 Earth days at a semi-major axis of 0.0875 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 112.5 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 1117 K (+844°C / +1551°F) and receiving 339.57 S⊕ (~462,159 W/m²), Kepler-1154 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1154 is classified as a stellar host with an effective photospheric temperature of 6,327 K, a radius of 1.43 R☉, a mass of 1.26 M☉, an estimated bolometric luminosity of 2.94 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.29 Gyr and a metallicity of [Fe/H] = 0.04 dex (near-solar heavy-element abundance). From Earth, Kepler-1154 shines at apparent V-band magnitude 14.953 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-1154 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-1154 c sharing its stellar neighborhood alongside Kepler-1154 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-1154 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,327 K |
| Stellar Radius | 1.4300 R☉ |
| Stellar Mass | 1.2600 M☉ |
| Bolometric Luminosity | 2.94 L☉ |
| Metallicity [Fe/H] | 0.040 dex |
| Stellar Age | 2.290 Gyr |
| Apparent Magnitude | V: 14.953 · G: 14.779 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.087500 AU |
| Orbital Period | 8.458 days |
| Mean Orbital Velocity | 112.5 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 87.5000° |
| Mean Bulk Density | 2.59 g/cm³ (18.1 km/s vesc) |
| Insolation Flux | 339.5730 S⊕ (~462,159 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 4762.200 LY (1460.100 pc) |