Kepler-101 b
Astrophysical Synthesis & Habitability Characterization
Kepler-101 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-101, located approximately 3026.7 light-years (927.98 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.115% across the stellar disk), this world measures 5.77 Earth radii (0.51 Jupiter radii) and has a measured mass of 51.1 Earth masses (0.16 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.47 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.53 g⊕ (15 m/s²), and an escape velocity of 33.3 km/s.
In its orbital architecture around Kepler-101, Kepler-101 b completes one full revolution every 3.488 Earth days at a semi-major axis of 0.0474 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 147.9 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.086 carries the world between 0.0433 AU at periapsis and 0.0515 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1513 K (+1240°C / +2264°F) and receiving 1,240.33 S⊕ (~1,688,092 W/m²), Kepler-101 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-101 is classified as a solar-type yellow star of spectral type G3 IV with an effective photospheric temperature of 5,667 K, a radius of 1.56 R☉, a mass of 1.17 M☉, an estimated bolometric luminosity of 2.252 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.9 Gyr and a metallicity of [Fe/H] = 0.33 dex (metal-rich relative to the Sun). From Earth, Kepler-101 shines at apparent V-band magnitude 13.7 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-101 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-101 b sharing its stellar neighborhood alongside Kepler-101 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-101 |
| Spectral Type | G3 IV |
| Effective Temp (Teff) | 5,667 K |
| Stellar Radius | 1.5600 R☉ |
| Stellar Mass | 1.1700 M☉ |
| Bolometric Luminosity | 2.252 L☉ |
| Metallicity [Fe/H] | 0.330 dex |
| Stellar Age | 5.900 Gyr |
| Apparent Magnitude | V: 13.700 · G: 13.567 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.047400 AU |
| Orbital Period | 3.488 days |
| Mean Orbital Velocity | 147.9 km/s |
| Orbital Eccentricity (e) | 0.08600 |
| Orbital Inclination (i) | 85.8200° |
| Mean Bulk Density | 1.47 g/cm³ (33.3 km/s vesc) |
| Insolation Flux | 1240.3320 S⊕ (~1,688,092 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 3026.700 LY (927.981 pc) |