K2-265 b
Astrophysical Synthesis & Habitability Characterization
K2-265 b is a confirmed super-earth exoplanet orbiting the star K2-265, located approximately 452.3 light-years (138.67 parsecs) from the Solar System. First announced in 2018 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.029% across the stellar disk), this world measures 1.708 Earth radii and has a measured mass of 7.342 Earth masses. Combining its mass and radius yields a mean bulk density of 8.12 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 2.52 g⊕ (24.71 m/s²), and an escape velocity of 23.2 km/s.
In its orbital architecture around K2-265, K2-265 b completes one full revolution every 2.369 Earth days at a semi-major axis of 0.03359 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 154.3 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.16 carries the world between 0.0282 AU at periapsis and 0.039 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1366 K (+1093°C / +1999°F) and receiving 592.00 S⊕ (~805,712 W/m²), K2-265 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star K2-265 is classified as a solar-type yellow star of spectral type G8 V with an effective photospheric temperature of 5,420 K, a radius of 0.92 R☉, a mass of 0.901 M☉, an estimated bolometric luminosity of 0.655 L☉. Stellar evolution modeling indicates an estimated stellar age of 7.8 Gyr and a metallicity of [Fe/H] = 0.033 dex (near-solar heavy-element abundance). From Earth, K2-265 shines at apparent V-band magnitude 11.187 (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 | K2-265 |
| Spectral Type | G8 V |
| Effective Temp (Teff) | 5,420 K |
| Stellar Radius | 0.9200 R☉ |
| Stellar Mass | 0.9010 M☉ |
| Bolometric Luminosity | 0.655 L☉ |
| Metallicity [Fe/H] | 0.033 dex |
| Stellar Age | 7.800 Gyr |
| Apparent Magnitude | V: 11.187 · G: 10.928 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.033590 AU |
| Orbital Period | 2.369 days |
| Mean Orbital Velocity | 154.3 km/s |
| Orbital Eccentricity (e) | 0.16000 |
| Orbital Inclination (i) | 87.0100° |
| Mean Bulk Density | 8.12 g/cm³ (23.2 km/s vesc) |
| Insolation Flux | 592.0000 S⊕ (~805,712 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 452.300 LY (138.671 pc) |