K2-147 b
Astrophysical Synthesis & Habitability Characterization
K2-147 b is a confirmed super-earth exoplanet orbiting the star K2-147, located approximately 295.3 light-years (90.55 parsecs) from the Solar System. First announced in 2018 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.0546% across the stellar disk), this world measures 1.473 Earth radii and has a measured mass of 2.77 Earth masses. Combining its mass and radius yields a mean bulk density of 4.78 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.28 g⊕ (12.55 m/s²), and an escape velocity of 15.3 km/s.
In its orbital architecture around K2-147, K2-147 b completes one full revolution every 0.962 Earth days at a semi-major axis of 0.01575 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 178.1 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.38, swinging from 0.0098 AU at periapsis out to 0.0217 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1077 K (+804°C / +1479°F) and receiving 200.10 S⊕ (~272,336 W/m²), K2-147 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star K2-147 is classified as a stellar host with an effective photospheric temperature of 3,690 K, a radius of 0.578 R☉, a mass of 0.563 M☉, an estimated bolometric luminosity of 0.056 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.02 dex (near-solar heavy-element abundance). From Earth, K2-147 shines at apparent V-band magnitude 14.044 (faint and requiring research-grade or CCD telescopic photometry) in the Southern celestial hemisphere.
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: K2 · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | K2-147 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 3,690 K |
| Stellar Radius | 0.5780 R☉ |
| Stellar Mass | 0.5630 M☉ |
| Bolometric Luminosity | 0.056 L☉ |
| Metallicity [Fe/H] | -0.020 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 14.044 · G: 13.191 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.015750 AU |
| Orbital Period | 0.962 days |
| Mean Orbital Velocity | 178.1 km/s |
| Orbital Eccentricity (e) | 0.38000 |
| Orbital Inclination (i) | 83.6000° |
| Mean Bulk Density | 4.78 g/cm³ (15.3 km/s vesc) |
| Insolation Flux | 200.1000 S⊕ (~272,336 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 295.300 LY (90.549 pc) |