Kepler-289 c
Astrophysical Synthesis & Habitability Characterization
Kepler-289 c is a confirmed gas giant exoplanet orbiting the star Kepler-289, located approximately 2297.6 light-years (704.44 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 1.06% across the stellar disk), this world measures 11.23 Earth radii (1 Jupiter radii) and has a measured mass of 157.18 Earth masses (0.49 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.61 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.25 g⊕ (12.26 m/s²), and an escape velocity of 41.8 km/s.
In its orbital architecture around Kepler-289, Kepler-289 c completes one full revolution every 125.872 Earth days at a semi-major axis of 0.50155 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 43.3 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 394 K (+121°C / +250°F) and receiving 4.88 S⊕ (~6,644 W/m²), Kepler-289 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-289 is classified as a stellar host with an effective photospheric temperature of 5,990 K, a radius of 1 R☉, a mass of 1.08 M☉, an estimated bolometric luminosity of 1.155 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.65 Gyr and a metallicity of [Fe/H] = 0.05 dex (near-solar heavy-element abundance). From Earth, Kepler-289 shines at apparent V-band magnitude 14.142 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-289 system is a multi-planet architecture hosting 4 confirmed worlds, with Kepler-289 c sharing its stellar neighborhood alongside Kepler-289 b, Kepler-289 d, Kepler-289 e.
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-289 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,990 K |
| Stellar Radius | 1.0000 R☉ |
| Stellar Mass | 1.0800 M☉ |
| Bolometric Luminosity | 1.155 L☉ |
| Metallicity [Fe/H] | 0.050 dex |
| Stellar Age | 0.650 Gyr |
| Apparent Magnitude | V: 14.142 · G: 13.963 |
| System Architecture | 1 Star, 4 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.501550 AU |
| Orbital Period | 125.872 days |
| Mean Orbital Velocity | 43.3 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.7800° |
| Mean Bulk Density | 0.61 g/cm³ (41.8 km/s vesc) |
| Insolation Flux | 4.8820 S⊕ (~6,644 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2297.600 LY (704.438 pc) |