Kepler-165 c
Astrophysical Synthesis & Habitability Characterization
Kepler-165 c is a confirmed sub-neptune exoplanet orbiting the star Kepler-165, located approximately 1829.4 light-years (560.89 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0705% across the stellar disk), this world measures 2.23 Earth radii and has a measured mass of 5.6 Earth masses. Combining its mass and radius yields a mean bulk density of 2.78 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.13 g⊕ (11.08 m/s²), and an escape velocity of 17.7 km/s.
In its orbital architecture around Kepler-165, Kepler-165 c completes one full revolution every 15.313 Earth days at a semi-major axis of 0.11 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 78.1 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 581 K (+308°C / +586°F) and receiving 25.93 S⊕ (~35,292 W/m²), Kepler-165 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-165 is classified as a stellar host with an effective photospheric temperature of 5,211 K, a radius of 0.77 R☉, a mass of 0.746 M☉, an estimated bolometric luminosity of 0.392 L☉. Stellar evolution modeling indicates an estimated stellar age of 10.5 Gyr and a metallicity of [Fe/H] = -0.25 dex (metal-poor relative to the Sun). From Earth, Kepler-165 shines at apparent V-band magnitude 15.05 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-165 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-165 c sharing its stellar neighborhood alongside Kepler-165 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-165 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,211 K |
| Stellar Radius | 0.7700 R☉ |
| Stellar Mass | 0.7460 M☉ |
| Bolometric Luminosity | 0.392 L☉ |
| Metallicity [Fe/H] | -0.250 dex |
| Stellar Age | 10.500 Gyr |
| Apparent Magnitude | V: 15.050 · G: 14.795 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.110000 AU |
| Orbital Period | 15.313 days |
| Mean Orbital Velocity | 78.1 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.8900° |
| Mean Bulk Density | 2.78 g/cm³ (17.7 km/s vesc) |
| Insolation Flux | 25.9310 S⊕ (~35,292 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1829.400 LY (560.885 pc) |