Kepler-159 c
Astrophysical Synthesis & Habitability Characterization
Kepler-159 c is a confirmed sub-neptune exoplanet orbiting the star Kepler-159, located approximately 1219 light-years (373.74 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.2223% across the stellar disk), this world measures 3.41 Earth radii (0.3 Jupiter radii) and has a measured mass of 11.5 Earth masses. Combining its mass and radius yields a mean bulk density of 1.6 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.99 g⊕ (9.71 m/s²), and an escape velocity of 20.5 km/s.
In its orbital architecture around Kepler-159, Kepler-159 c completes one full revolution every 43.596 Earth days at a semi-major axis of 0.218 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 54.4 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.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 3.410 R⊕, Kepler-159 c exceeds the empirical ~1.8–2.2 R⊕ Fulton radius valley threshold, indicating a substantial hydrogen-helium or supercritical volatile envelope without a conventional solid terrestrial surface.
The host star Kepler-159 is classified as a low-mass red dwarf of spectral type M0 V with an effective photospheric temperature of 4,625 K, a radius of 0.663 R☉, a mass of 0.628 M☉, an estimated bolometric luminosity of 0.18 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.51 Gyr and a metallicity of [Fe/H] = -0.04 dex (near-solar heavy-element abundance). From Earth, Kepler-159 shines at apparent V-band magnitude 15.386 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-159 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-159 c sharing its stellar neighborhood alongside Kepler-159 b.
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-159 |
| Spectral Type | M0 V |
| Effective Temp (Teff) | 4,625 K |
| Stellar Radius | 0.6630 R☉ |
| Stellar Mass | 0.6280 M☉ |
| Bolometric Luminosity | 0.18 L☉ |
| Metallicity [Fe/H] | -0.040 dex |
| Stellar Age | 2.510 Gyr |
| Apparent Magnitude | V: 15.386 · G: 14.888 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.218000 AU |
| Orbital Period | 43.596 days |
| Mean Orbital Velocity | 54.4 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.9900° |
| Mean Bulk Density | 1.6 g/cm³ (20.5 km/s vesc) |
| Insolation Flux | 4.7910 S⊕ (~6,521 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1219.000 LY (373.744 pc) |