K2-271 b
Astrophysical Synthesis & Habitability Characterization
K2-271 b is a confirmed gas giant exoplanet orbiting the star K2-271, located approximately 1841 light-years (564.45 parsecs) from the Solar System. First announced in 2018 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.4545% across the stellar disk), this world measures 7.28 Earth radii (0.65 Jupiter radii) and has a measured mass of 41.8 Earth masses (0.13 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.6 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.79 g⊕ (7.75 m/s²), and an escape velocity of 26.8 km/s.
In its orbital architecture around K2-271, K2-271 b completes one full revolution every 8.562 Earth days at a semi-major axis of 0.077 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 97.8 km/s (compared to Earth's 29.8 km/s).
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 893 K (+620°C / +1148°F) and receiving 133.81 S⊕ (~182,111 W/m²), K2-271 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star K2-271 is classified as a stellar host with an effective photospheric temperature of 5,644 K, a radius of 0.99 R☉, a mass of 0.83 M☉, an estimated bolometric luminosity of 0.892 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.3 dex (metal-poor relative to the Sun). From Earth, K2-271 shines at apparent V-band magnitude 13.845 (faint and requiring research-grade or CCD telescopic photometry) in the Northern 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 | K2-271 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,644 K |
| Stellar Radius | 0.9900 R☉ |
| Stellar Mass | 0.8300 M☉ |
| Bolometric Luminosity | 0.892 L☉ |
| Metallicity [Fe/H] | -0.300 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 13.845 · G: 13.658 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.077000 AU |
| Orbital Period | 8.562 days |
| Mean Orbital Velocity | 97.8 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.6 g/cm³ (26.8 km/s vesc) |
| Insolation Flux | 133.8067 S⊕ (~182,111 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1841.000 LY (564.454 pc) |