Kepler-389 c
Astrophysical Synthesis & Habitability Characterization
Kepler-389 c is a confirmed super-earth exoplanet orbiting the star Kepler-389, located approximately 2663.3 light-years (816.56 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0286% across the stellar disk), this world measures 1.46 Earth radii and has a measured mass of 2.73 Earth masses. Combining its mass and radius yields a mean bulk density of 4.84 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-389, Kepler-389 c completes one full revolution every 14.511 Earth days at a semi-major axis of 0.11 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 82.5 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 636 K (+363°C / +685°F) and receiving 22.74 S⊕ (~30,942 W/m²), Kepler-389 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-389 is classified as a stellar host with an effective photospheric temperature of 5,376 K, a radius of 0.792 R☉, a mass of 0.765 M☉, an estimated bolometric luminosity of 0.47 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.86 Gyr and a metallicity of [Fe/H] = -0.1 dex (near-solar heavy-element abundance). From Earth, Kepler-389 shines at apparent V-band magnitude 15.769 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-389 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-389 c sharing its stellar neighborhood alongside Kepler-389 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-389 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,376 K |
| Stellar Radius | 0.7920 R☉ |
| Stellar Mass | 0.7650 M☉ |
| Bolometric Luminosity | 0.47 L☉ |
| Metallicity [Fe/H] | -0.100 dex |
| Stellar Age | 1.860 Gyr |
| Apparent Magnitude | V: 15.769 · G: 15.750 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.110000 AU |
| Orbital Period | 14.511 days |
| Mean Orbital Velocity | 82.5 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 85.3800° |
| Mean Bulk Density | 4.84 g/cm³ (15.3 km/s vesc) |
| Insolation Flux | 22.7350 S⊕ (~30,942 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2663.300 LY (816.559 pc) |