Kepler-1090 c
Astrophysical Synthesis & Habitability Characterization
Kepler-1090 c is a confirmed sub-neptune exoplanet orbiting the star Kepler-1090, located approximately 2800.9 light-years (858.77 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0888% across the stellar disk), this world measures 3.293 Earth radii (0.29 Jupiter radii) and has a measured mass of 10.9 Earth masses. Combining its mass and radius yields a mean bulk density of 1.68 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.01 g⊕ (9.9 m/s²), and an escape velocity of 20.4 km/s.
In its orbital architecture around Kepler-1090, Kepler-1090 c completes one full revolution every 42.427 Earth days at a semi-major axis of 0.22622 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 58 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 496 K (+223°C / +433°F) and receiving 13.80 S⊕ (~18,782 W/m²), Kepler-1090 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1090 is classified as a stellar host with an effective photospheric temperature of 5,330 K, a radius of 1.013 R☉, a mass of 0.869 M☉, an estimated bolometric luminosity of 0.743 L☉. Stellar evolution modeling indicates an estimated stellar age of 12.59 Gyr and a metallicity of [Fe/H] = 0.18 dex (metal-rich relative to the Sun). From Earth, Kepler-1090 shines at apparent V-band magnitude 15.31 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-1090 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-1090 c sharing its stellar neighborhood alongside Kepler-1090 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-1090 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,330 K |
| Stellar Radius | 1.0130 R☉ |
| Stellar Mass | 0.8690 M☉ |
| Bolometric Luminosity | 0.743 L☉ |
| Metallicity [Fe/H] | 0.180 dex |
| Stellar Age | 12.590 Gyr |
| Apparent Magnitude | V: 15.310 · G: 14.996 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.226220 AU |
| Orbital Period | 42.427 days |
| Mean Orbital Velocity | 58 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 87.3000° |
| Mean Bulk Density | 1.68 g/cm³ (20.4 km/s vesc) |
| Insolation Flux | 13.8000 S⊕ (~18,782 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2800.900 LY (858.770 pc) |