Kepler-770 d
Astrophysical Synthesis & Habitability Characterization
Kepler-770 d is a confirmed super-earth exoplanet orbiting the star Kepler-770, located approximately 3034.7 light-years (930.46 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0195% across the stellar disk), this world measures 1.4 Earth radii and has a measured mass of 2.54 Earth masses. Combining its mass and radius yields a mean bulk density of 5.1 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.3 g⊕ (12.75 m/s²), and an escape velocity of 15.1 km/s.
In its orbital architecture around Kepler-770, Kepler-770 d completes one full revolution every 4.152 Earth days at a semi-major axis of 0.0616 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 161.4 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 1941 K (+1668°C / +3034°F) and receiving 209.75 S⊕ (~285,472 W/m²), Kepler-770 d orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-770 is classified as a stellar host with an effective photospheric temperature of 5,598 K, a radius of 0.92 R☉, a mass of 0.94 M☉, an estimated bolometric luminosity of 0.746 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.57 Gyr and a metallicity of [Fe/H] = -0.01 dex (near-solar heavy-element abundance). From Earth, Kepler-770 shines at apparent V-band magnitude 14.852 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-770 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-770 d sharing its stellar neighborhood alongside Kepler-770 c, Kepler-770 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-770 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,598 K |
| Stellar Radius | 0.9200 R☉ |
| Stellar Mass | 0.9400 M☉ |
| Bolometric Luminosity | 0.746 L☉ |
| Metallicity [Fe/H] | -0.010 dex |
| Stellar Age | 4.570 Gyr |
| Apparent Magnitude | V: 14.852 · G: 14.597 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.061600 AU |
| Orbital Period | 4.152 days |
| Mean Orbital Velocity | 161.4 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 86.2400° |
| Mean Bulk Density | 5.1 g/cm³ (15.1 km/s vesc) |
| Insolation Flux | 209.7520 S⊕ (~285,472 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 3034.700 LY (930.457 pc) |