Kepler-953 b
Astrophysical Synthesis & Habitability Characterization
Kepler-953 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-953, located approximately 844.4 light-years (258.89 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.152% across the stellar disk), this world measures 4.21 Earth radii (0.38 Jupiter radii) and has a measured mass of 16.5 Earth masses. Combining its mass and radius yields a mean bulk density of 1.22 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.93 g⊕ (9.12 m/s²), and an escape velocity of 22.1 km/s.
In its orbital architecture around Kepler-953, Kepler-953 b completes one full revolution every 88.407 Earth days at a semi-major axis of 0.392 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 48.2 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 410 K (+137°C / +279°F) and receiving 5.84 S⊕ (~7,948 W/m²), Kepler-953 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-953 is classified as a stellar host with an effective photospheric temperature of 5,416 K, a radius of 0.99 R☉, a mass of 0.95 M☉, an estimated bolometric luminosity of 0.757 L☉. Stellar evolution modeling indicates an estimated stellar age of 8.71 Gyr and a metallicity of [Fe/H] = 0.26 dex (metal-rich relative to the Sun). From Earth, Kepler-953 shines at apparent V-band magnitude 11.871 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-953 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-953 b sharing its stellar neighborhood alongside Kepler-953 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-953 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,416 K |
| Stellar Radius | 0.9900 R☉ |
| Stellar Mass | 0.9500 M☉ |
| Bolometric Luminosity | 0.757 L☉ |
| Metallicity [Fe/H] | 0.260 dex |
| Stellar Age | 8.710 Gyr |
| Apparent Magnitude | V: 11.871 · G: 12.143 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.392000 AU |
| Orbital Period | 88.407 days |
| Mean Orbital Velocity | 48.2 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.3700° |
| Mean Bulk Density | 1.22 g/cm³ (22.1 km/s vesc) |
| Insolation Flux | 5.8400 S⊕ (~7,948 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 844.400 LY (258.893 pc) |