Kepler-161 b
Astrophysical Synthesis & Habitability Characterization
Kepler-161 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-161, located approximately 1417.6 light-years (434.63 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0581% across the stellar disk), this world measures 2.12 Earth radii and has a measured mass of 2.63 Earth masses. Combining its mass and radius yields a mean bulk density of 1.52 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.59 g⊕ (5.79 m/s²), and an escape velocity of 12.5 km/s.
In its orbital architecture around Kepler-161, Kepler-161 b completes one full revolution every 4.921 Earth days at a semi-major axis of 0.054 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 119.4 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 868 K (+595°C / +1103°F) and receiving 123.40 S⊕ (~167,947 W/m²), Kepler-161 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-161 is classified as a stellar host with an effective photospheric temperature of 5,078 K, a radius of 0.806 R☉, a mass of 0.853 M☉, an estimated bolometric luminosity of 0.388 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.91 Gyr and a metallicity of [Fe/H] = 0.24 dex (metal-rich relative to the Sun). From Earth, Kepler-161 shines at apparent V-band magnitude 14.406 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-161 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-161 b sharing its stellar neighborhood alongside Kepler-161 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-161 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,078 K |
| Stellar Radius | 0.8060 R☉ |
| Stellar Mass | 0.8530 M☉ |
| Bolometric Luminosity | 0.388 L☉ |
| Metallicity [Fe/H] | 0.240 dex |
| Stellar Age | 0.910 Gyr |
| Apparent Magnitude | V: 14.406 · G: 14.192 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.054000 AU |
| Orbital Period | 4.921 days |
| Mean Orbital Velocity | 119.4 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.9300° |
| Mean Bulk Density | 1.52 g/cm³ (12.5 km/s vesc) |
| Insolation Flux | 123.4000 S⊕ (~167,947 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1417.600 LY (434.632 pc) |