Kepler-616 c
Astrophysical Synthesis & Habitability Characterization
Kepler-616 c is a confirmed sub-neptune exoplanet orbiting the star Kepler-616, located approximately 3084.7 light-years (945.78 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.1039% across the stellar disk), this world measures 3.41 Earth radii (0.3 Jupiter radii) and has a measured mass of 11.5 Earth masses. Combining its mass and radius yields a mean bulk density of 1.6 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.99 g⊕ (9.71 m/s²), and an escape velocity of 20.5 km/s.
In its orbital architecture around Kepler-616, Kepler-616 c completes one full revolution every 90.411 Earth days at a semi-major axis of 0.4024 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 48.4 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 413 K (+140°C / +284°F) and receiving 6.86 S⊕ (~9,336 W/m²), Kepler-616 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-616 is classified as a stellar host with an effective photospheric temperature of 5,753 K, a radius of 0.97 R☉, a mass of 0.98 M☉, an estimated bolometric luminosity of 0.925 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.89 Gyr and a metallicity of [Fe/H] = -0.02 dex (near-solar heavy-element abundance). From Earth, Kepler-616 shines at apparent V-band magnitude 15.021 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-616 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-616 c sharing its stellar neighborhood alongside Kepler-616 b, Kepler-616 d.
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-616 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,753 K |
| Stellar Radius | 0.9700 R☉ |
| Stellar Mass | 0.9800 M☉ |
| Bolometric Luminosity | 0.925 L☉ |
| Metallicity [Fe/H] | -0.020 dex |
| Stellar Age | 3.890 Gyr |
| Apparent Magnitude | V: 15.021 · G: 14.948 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.402400 AU |
| Orbital Period | 90.411 days |
| Mean Orbital Velocity | 48.4 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.1600° |
| Mean Bulk Density | 1.6 g/cm³ (20.5 km/s vesc) |
| Insolation Flux | 6.8600 S⊕ (~9,336 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 3084.700 LY (945.775 pc) |