Kepler-780 b
Astrophysical Synthesis & Habitability Characterization
Kepler-780 b is a confirmed terrestrial exoplanet orbiting the star Kepler-780, located approximately 1818.8 light-years (557.65 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0064% across the stellar disk), this world measures 0.89 Earth radii and has a measured mass of 0.64 Earth masses. Combining its mass and radius yields a mean bulk density of 5.01 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 0.81 g⊕ (7.94 m/s²), and an escape velocity of 9.5 km/s.
In its orbital architecture around Kepler-780, Kepler-780 b completes one full revolution every 0.677 Earth days at a semi-major axis of 0.015 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 240.9 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 2099 K (+1826°C / +3319°F) and receiving 4,572.56 S⊕ (~6,223,254 W/m²), Kepler-780 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-780 is classified as a stellar host with an effective photospheric temperature of 5,769 K, a radius of 1.02 R☉, a mass of 1.01 M☉, an estimated bolometric luminosity of 1.034 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.9 Gyr and a metallicity of [Fe/H] = 0.05 dex (near-solar heavy-element abundance). From Earth, Kepler-780 shines at apparent V-band magnitude 13.464 (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-780 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,769 K |
| Stellar Radius | 1.0200 R☉ |
| Stellar Mass | 1.0100 M☉ |
| Bolometric Luminosity | 1.034 L☉ |
| Metallicity [Fe/H] | 0.050 dex |
| Stellar Age | 4.900 Gyr |
| Apparent Magnitude | V: 13.464 · G: 13.339 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.015000 AU |
| Orbital Period | 0.677 days |
| Mean Orbital Velocity | 240.9 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 87.3800° |
| Mean Bulk Density | 5.01 g/cm³ (9.5 km/s vesc) |
| Insolation Flux | 4572.5600 S⊕ (~6,223,254 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1818.800 LY (557.652 pc) |