Kepler-449 c
Astrophysical Synthesis & Habitability Characterization
Kepler-449 c is a confirmed sub-neptune exoplanet orbiting the star Kepler-449, located approximately 789.1 light-years (241.95 parsecs) from the Solar System. First announced in 2015 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0298% across the stellar disk), this world measures 2.764 Earth radii and has a measured mass of 8.07 Earth masses. Combining its mass and radius yields a mean bulk density of 2.11 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.06 g⊕ (10.4 m/s²), and an escape velocity of 19.1 km/s.
In its orbital architecture around Kepler-449, Kepler-449 c completes one full revolution every 33.673 Earth days at a semi-major axis of 0.1979 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 63.9 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.05 carries the world between 0.188 AU at periapsis and 0.2078 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 661 K (+388°C / +730°F) and receiving 45.09 S⊕ (~61,367 W/m²), Kepler-449 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-449 is classified as a stellar host with an effective photospheric temperature of 5,649 K, a radius of 1.467 R☉, a mass of 1.02 M☉, an estimated bolometric luminosity of 1.966 L☉. Stellar evolution modeling indicates an estimated stellar age of 9.77 Gyr and a metallicity of [Fe/H] = -0.165 dex (metal-poor relative to the Sun). From Earth, Kepler-449 shines at apparent V-band magnitude 11.448 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-449 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-449 c sharing its stellar neighborhood alongside Kepler-449 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-449 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,649 K |
| Stellar Radius | 1.4670 R☉ |
| Stellar Mass | 1.0200 M☉ |
| Bolometric Luminosity | 1.966 L☉ |
| Metallicity [Fe/H] | -0.165 dex |
| Stellar Age | 9.770 Gyr |
| Apparent Magnitude | V: 11.448 · G: 11.226 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.197900 AU |
| Orbital Period | 33.673 days |
| Mean Orbital Velocity | 63.9 km/s |
| Orbital Eccentricity (e) | 0.05000 |
| Orbital Inclination (i) | 89.4100° |
| Mean Bulk Density | 2.11 g/cm³ (19.1 km/s vesc) |
| Insolation Flux | 45.0900 S⊕ (~61,367 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 789.100 LY (241.949 pc) |