K2-44 b
Astrophysical Synthesis & Habitability Characterization
K2-44 b is a confirmed sub-neptune exoplanet orbiting the star K2-44, located approximately 1554.8 light-years (476.7 parsecs) from the Solar System. First announced in 2016 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.0199% across the stellar disk), this world measures 2.433 Earth radii and has a measured mass of 6.5 Earth masses. Combining its mass and radius yields a mean bulk density of 2.49 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.1 g⊕ (10.79 m/s²), and an escape velocity of 18.3 km/s.
In its orbital architecture around K2-44, K2-44 b completes one full revolution every 5.657 Earth days at a semi-major axis of 0.06 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 115.4 km/s (compared to Earth's 29.8 km/s).
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1211 K (+938°C / +1720°F) and receiving 646.00 S⊕ (~879,206 W/m²), K2-44 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star K2-44 is classified as a stellar host with an effective photospheric temperature of 5,912 K, a radius of 1.58 R☉, a mass of 1.15 M☉, an estimated bolometric luminosity of 2.736 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0 dex (near-solar heavy-element abundance). From Earth, K2-44 shines at apparent V-band magnitude 12.27 (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 | K2-44 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,912 K |
| Stellar Radius | 1.5800 R☉ |
| Stellar Mass | 1.1500 M☉ |
| Bolometric Luminosity | 2.736 L☉ |
| Metallicity [Fe/H] | 0.000 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 12.270 · G: 12.024 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.060000 AU |
| Orbital Period | 5.657 days |
| Mean Orbital Velocity | 115.4 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 87.9933° |
| Mean Bulk Density | 2.49 g/cm³ (18.3 km/s vesc) |
| Insolation Flux | 646.0000 S⊕ (~879,206 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1554.800 LY (476.703 pc) |