Kepler-153 b
Astrophysical Synthesis & Habitability Characterization
Kepler-153 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-153, located approximately 1498.3 light-years (459.37 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0901% across the stellar disk), this world measures 2.92 Earth radii and has a measured mass of 8.85 Earth masses. Combining its mass and radius yields a mean bulk density of 1.96 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.04 g⊕ (10.2 m/s²), and an escape velocity of 19.5 km/s.
In its orbital architecture around Kepler-153, Kepler-153 b completes one full revolution every 18.87 Earth days at a semi-major axis of 0.129 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 74.4 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 621 K (+348°C / +658°F) and receiving 21.61 S⊕ (~29,410 W/m²), Kepler-153 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-153 is classified as a stellar host with an effective photospheric temperature of 5,404 K, a radius of 0.892 R☉, a mass of 0.756 M☉, an estimated bolometric luminosity of 0.609 L☉. Stellar evolution modeling indicates an estimated stellar age of 13.8 Gyr and a metallicity of [Fe/H] = -0.27 dex (metal-poor relative to the Sun). From Earth, Kepler-153 shines at apparent V-band magnitude 14.388 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-153 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-153 b sharing its stellar neighborhood alongside Kepler-153 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-153 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,404 K |
| Stellar Radius | 0.8920 R☉ |
| Stellar Mass | 0.7560 M☉ |
| Bolometric Luminosity | 0.609 L☉ |
| Metallicity [Fe/H] | -0.270 dex |
| Stellar Age | 13.800 Gyr |
| Apparent Magnitude | V: 14.388 · G: 14.249 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.129000 AU |
| Orbital Period | 18.87 days |
| Mean Orbital Velocity | 74.4 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.9800° |
| Mean Bulk Density | 1.96 g/cm³ (19.5 km/s vesc) |
| Insolation Flux | 21.6090 S⊕ (~29,410 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1498.300 LY (459.368 pc) |