Kepler-589 b
Astrophysical Synthesis & Habitability Characterization
Kepler-589 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-589, located approximately 1998.7 light-years (612.8 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0629% across the stellar disk), this world measures 2.27 Earth radii and has a measured mass of 5.77 Earth masses. Combining its mass and radius yields a mean bulk density of 2.72 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.12 g⊕ (10.98 m/s²), and an escape velocity of 17.8 km/s.
In its orbital architecture around Kepler-589, Kepler-589 b completes one full revolution every 16.55 Earth days at a semi-major axis of 0.1196 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 78.6 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 656 K (+383°C / +721°F) and receiving 32.14 S⊕ (~43,745 W/m²), Kepler-589 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-589 is classified as a stellar host with an effective photospheric temperature of 5,296 K, a radius of 0.83 R☉, a mass of 0.88 M☉, an estimated bolometric luminosity of 0.486 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.47 Gyr and a metallicity of [Fe/H] = 0.01 dex (near-solar heavy-element abundance). From Earth, Kepler-589 shines at apparent V-band magnitude 14.775 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-589 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-589 b sharing its stellar neighborhood alongside Kepler-589 c.
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-589 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,296 K |
| Stellar Radius | 0.8300 R☉ |
| Stellar Mass | 0.8800 M☉ |
| Bolometric Luminosity | 0.486 L☉ |
| Metallicity [Fe/H] | 0.010 dex |
| Stellar Age | 4.470 Gyr |
| Apparent Magnitude | V: 14.775 · G: 14.661 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.119600 AU |
| Orbital Period | 16.55 days |
| Mean Orbital Velocity | 78.6 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 86.7400° |
| Mean Bulk Density | 2.72 g/cm³ (17.8 km/s vesc) |
| Insolation Flux | 32.1420 S⊕ (~43,745 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1998.700 LY (612.803 pc) |