Kepler-1518 c
Astrophysical Synthesis & Habitability Characterization
Kepler-1518 c is a confirmed sub-neptune exoplanet orbiting the star Kepler-1518, located approximately 2946.9 light-years (903.51 parsecs) from the Solar System. First announced in 2023 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0391% across the stellar disk), this world measures 2.9 Earth radii and has a measured mass of 8.75 Earth masses. Combining its mass and radius yields a mean bulk density of 1.98 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.04 g⊕ (10.2 m/s²), and an escape velocity of 19.4 km/s.
In its orbital architecture around Kepler-1518, Kepler-1518 c completes one full revolution every 9.631 Earth days at a semi-major axis of 0.0905 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 102.2 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 1094 K (+821°C / +1510°F) and receiving 338.33 S⊕ (~460,467 W/m²), Kepler-1518 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1518 is classified as a stellar host with an effective photospheric temperature of 6,432 K, a radius of 1.345 R☉, a mass of 1.06 M☉, an estimated bolometric luminosity of 2.778 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.48 Gyr and a metallicity of [Fe/H] = -0.34 dex (metal-poor relative to the Sun). From Earth, Kepler-1518 shines at apparent V-band magnitude 13.374 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-1518 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-1518 c sharing its stellar neighborhood alongside Kepler-1518 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-1518 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,432 K |
| Stellar Radius | 1.3450 R☉ |
| Stellar Mass | 1.0600 M☉ |
| Bolometric Luminosity | 2.778 L☉ |
| Metallicity [Fe/H] | -0.340 dex |
| Stellar Age | 1.480 Gyr |
| Apparent Magnitude | V: 13.374 · G: 13.280 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.090500 AU |
| Orbital Period | 9.631 days |
| Mean Orbital Velocity | 102.2 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 79.5600° |
| Mean Bulk Density | 1.98 g/cm³ (19.4 km/s vesc) |
| Insolation Flux | 338.3300 S⊕ (~460,467 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2946.900 LY (903.510 pc) |