Kepler-287 c
Astrophysical Synthesis & Habitability Characterization
Kepler-287 c is a confirmed sub-neptune exoplanet orbiting the star Kepler-287, located approximately 2726.2 light-years (835.86 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0839% across the stellar disk), this world measures 3.26 Earth radii (0.29 Jupiter radii) and has a measured mass of 66 Earth masses (0.21 Jupiter masses). Combining its mass and radius yields a mean bulk density of 10.5 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 6.21 g⊕ (60.9 m/s²), and an escape velocity of 50.3 km/s.
In its orbital architecture around Kepler-287, Kepler-287 c completes one full revolution every 44.852 Earth days at a semi-major axis of 0.246 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 59.7 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 513 K (+240°C / +464°F) and receiving 12.46 S⊕ (~16,954 W/m²), Kepler-287 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-287 is classified as an orange K-type star of spectral type K7 V with an effective photospheric temperature of 5,806 K, a radius of 1.032 R☉, a mass of 0.963 M☉, an estimated bolometric luminosity of 1.086 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.88 Gyr and a metallicity of [Fe/H] = 0.117 dex (metal-rich relative to the Sun). From Earth, Kepler-287 shines at apparent V-band magnitude 14.952 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-287 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-287 c sharing its stellar neighborhood alongside Kepler-287 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-287 |
| Spectral Type | K7 V |
| Effective Temp (Teff) | 5,806 K |
| Stellar Radius | 1.0320 R☉ |
| Stellar Mass | 0.9630 M☉ |
| Bolometric Luminosity | 1.086 L☉ |
| Metallicity [Fe/H] | 0.117 dex |
| Stellar Age | 2.880 Gyr |
| Apparent Magnitude | V: 14.952 · G: 14.744 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.246000 AU |
| Orbital Period | 44.852 days |
| Mean Orbital Velocity | 59.7 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.2400° |
| Mean Bulk Density | 10.5 g/cm³ (50.3 km/s vesc) |
| Insolation Flux | 12.4570 S⊕ (~16,954 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2726.200 LY (835.860 pc) |