Kepler-617 b
Astrophysical Synthesis & Habitability Characterization
Kepler-617 b is a confirmed super-earth exoplanet orbiting the star Kepler-617, located approximately 565.4 light-years (173.35 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0636% across the stellar disk), this world measures 1.32 Earth radii and has a measured mass of 2.3 Earth masses. Combining its mass and radius yields a mean bulk density of 5.51 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.32 g⊕ (12.94 m/s²), and an escape velocity of 14.8 km/s.
In its orbital architecture around Kepler-617, Kepler-617 b completes one full revolution every 1.683 Earth days at a semi-major axis of 0.0219 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 141.6 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 750 K (+477°C / +891°F) and receiving 100.30 S⊕ (~136,501 W/m²), Kepler-617 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-617 is classified as a low-mass red dwarf of spectral type M1 V with an effective photospheric temperature of 3,712 K, a radius of 0.48 R☉, a mass of 0.51 M☉, an estimated bolometric luminosity of 0.039 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.98 Gyr and a metallicity of [Fe/H] = -0.07 dex (near-solar heavy-element abundance). From Earth, Kepler-617 shines at apparent V-band magnitude 15.549 (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-617 |
| Spectral Type | M1 V |
| Effective Temp (Teff) | 3,712 K |
| Stellar Radius | 0.4800 R☉ |
| Stellar Mass | 0.5100 M☉ |
| Bolometric Luminosity | 0.039 L☉ |
| Metallicity [Fe/H] | -0.070 dex |
| Stellar Age | 3.980 Gyr |
| Apparent Magnitude | V: 15.549 · G: 14.828 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.021900 AU |
| Orbital Period | 1.683 days |
| Mean Orbital Velocity | 141.6 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.8500° |
| Mean Bulk Density | 5.51 g/cm³ (14.8 km/s vesc) |
| Insolation Flux | 100.2950 S⊕ (~136,501 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 565.400 LY (173.354 pc) |