K2-272 b
Astrophysical Synthesis & Habitability Characterization
K2-272 b is a confirmed sub-neptune exoplanet orbiting the star K2-272, located approximately 1379.9 light-years (423.07 parsecs) from the Solar System. First announced in 2018 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.1195% across the stellar disk), this world measures 3.13 Earth radii (0.28 Jupiter radii) and has a measured mass of 9.96 Earth masses. Combining its mass and radius yields a mean bulk density of 1.79 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.02 g⊕ (10 m/s²), and an escape velocity of 20 km/s.
In its orbital architecture around K2-272, K2-272 b completes one full revolution every 14.454 Earth days at a semi-major axis of 0.1007 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 75.8 km/s (compared to Earth's 29.8 km/s).
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 747 K (+474°C / +885°F) and receiving 49.18 S⊕ (~66,935 W/m²), K2-272 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star K2-272 is classified as a stellar host with an effective photospheric temperature of 5,397 K, a radius of 0.83 R☉, a mass of 0.86 M☉, an estimated bolometric luminosity of 0.524 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.09 dex (near-solar heavy-element abundance). From Earth, K2-272 shines at apparent V-band magnitude 13.872 (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 | K2-272 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,397 K |
| Stellar Radius | 0.8300 R☉ |
| Stellar Mass | 0.8600 M☉ |
| Bolometric Luminosity | 0.524 L☉ |
| Metallicity [Fe/H] | -0.090 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 13.872 · G: 13.667 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.100700 AU |
| Orbital Period | 14.454 days |
| Mean Orbital Velocity | 75.8 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.79 g/cm³ (20 km/s vesc) |
| Insolation Flux | 49.1810 S⊕ (~66,935 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1379.900 LY (423.065 pc) |