Kepler-777 b
Astrophysical Synthesis & Habitability Characterization
Kepler-777 b is a confirmed super-earth exoplanet orbiting the star Kepler-777, located approximately 1445.2 light-years (443.11 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0579% across the stellar disk), this world measures 1.47 Earth radii and has a measured mass of 2.76 Earth masses. Combining its mass and radius yields a mean bulk density of 4.79 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.28 g⊕ (12.55 m/s²), and an escape velocity of 15.3 km/s.
In its orbital architecture around Kepler-777, Kepler-777 b completes one full revolution every 5.728 Earth days at a semi-major axis of 0.0519 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 98.6 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 569 K (+296°C / +565°F) and receiving 33.95 S⊕ (~46,210 W/m²), Kepler-777 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-777 is classified as a stellar host with an effective photospheric temperature of 4,043 K, a radius of 0.56 R☉, a mass of 0.58 M☉, an estimated bolometric luminosity of 0.075 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.16 Gyr and a metallicity of [Fe/H] = -0.17 dex (metal-poor relative to the Sun). From Earth, Kepler-777 shines at apparent V-band magnitude 16.131 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.
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-777 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,043 K |
| Stellar Radius | 0.5600 R☉ |
| Stellar Mass | 0.5800 M☉ |
| Bolometric Luminosity | 0.075 L☉ |
| Metallicity [Fe/H] | -0.170 dex |
| Stellar Age | 3.160 Gyr |
| Apparent Magnitude | V: 16.131 · G: 15.940 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.051900 AU |
| Orbital Period | 5.728 days |
| Mean Orbital Velocity | 98.6 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.4200° |
| Mean Bulk Density | 4.79 g/cm³ (15.3 km/s vesc) |
| Insolation Flux | 33.9530 S⊕ (~46,210 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1445.200 LY (443.106 pc) |