Kepler-598 b
Astrophysical Synthesis & Habitability Characterization
Kepler-598 b is a confirmed super-earth exoplanet orbiting the star Kepler-598, located approximately 2221.4 light-years (681.09 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0256% across the stellar disk), this world measures 1.5 Earth radii and has a measured mass of 2.86 Earth masses. Combining its mass and radius yields a mean bulk density of 4.67 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.27 g⊕ (12.45 m/s²), and an escape velocity of 15.4 km/s.
In its orbital architecture around Kepler-598, Kepler-598 b completes one full revolution every 3.702 Earth days at a semi-major axis of 0.04487 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 131.9 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 1050 K (+777°C / +1431°F) and receiving 265.41 S⊕ (~361,219 W/m²), Kepler-598 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-598 is classified as a stellar host with an effective photospheric temperature of 5,307 K, a radius of 0.86 R☉, a mass of 0.87 M☉, an estimated bolometric luminosity of 0.526 L☉. Stellar evolution modeling indicates an estimated stellar age of 7.59 Gyr and a metallicity of [Fe/H] = 0.02 dex (near-solar heavy-element abundance). From Earth, Kepler-598 shines at apparent V-band magnitude 14.829 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-598 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-598 b sharing its stellar neighborhood alongside Kepler-598 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-598 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,307 K |
| Stellar Radius | 0.8600 R☉ |
| Stellar Mass | 0.8700 M☉ |
| Bolometric Luminosity | 0.526 L☉ |
| Metallicity [Fe/H] | 0.020 dex |
| Stellar Age | 7.590 Gyr |
| Apparent Magnitude | V: 14.829 · G: 14.721 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.044870 AU |
| Orbital Period | 3.702 days |
| Mean Orbital Velocity | 131.9 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 84.8300° |
| Mean Bulk Density | 4.67 g/cm³ (15.4 km/s vesc) |
| Insolation Flux | 265.4070 S⊕ (~361,219 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2221.400 LY (681.086 pc) |