Kepler-993 b
Astrophysical Synthesis & Habitability Characterization
Kepler-993 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-993, located approximately 1058.1 light-years (324.42 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.2543% across the stellar disk), this world measures 2.97 Earth radii and has a measured mass of 9.11 Earth masses. Combining its mass and radius yields a mean bulk density of 1.92 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.03 g⊕ (10.1 m/s²), and an escape velocity of 19.6 km/s.
In its orbital architecture around Kepler-993, Kepler-993 b completes one full revolution every 22.086 Earth days at a semi-major axis of 0.13 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 64 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 352 K (+79°C / +174°F) and receiving 3.95 S⊕ (~5,381 W/m²), Kepler-993 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-993 is classified as a stellar host with an effective photospheric temperature of 3,843 K, a radius of 0.54 R☉, a mass of 0.57 M☉, an estimated bolometric luminosity of 0.057 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.89 Gyr and a metallicity of [Fe/H] = 0.03 dex (near-solar heavy-element abundance). From Earth, Kepler-993 shines at apparent V-band magnitude 16.608 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.
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-993 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 3,843 K |
| Stellar Radius | 0.5400 R☉ |
| Stellar Mass | 0.5700 M☉ |
| Bolometric Luminosity | 0.057 L☉ |
| Metallicity [Fe/H] | 0.030 dex |
| Stellar Age | 3.890 Gyr |
| Apparent Magnitude | V: 16.608 · G: 15.924 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.130000 AU |
| Orbital Period | 22.086 days |
| Mean Orbital Velocity | 64 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.4100° |
| Mean Bulk Density | 1.92 g/cm³ (19.6 km/s vesc) |
| Insolation Flux | 3.9540 S⊕ (~5,381 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1058.100 LY (324.423 pc) |