K2-183 d
Astrophysical Synthesis & Habitability Characterization
K2-183 d is a confirmed sub-neptune exoplanet orbiting the star K2-183, located approximately 1073.2 light-years (329.04 parsecs) from the Solar System. First announced in 2018 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.0587% across the stellar disk), this world measures 2.3 Earth radii and has a measured mass of 5.9 Earth masses. Combining its mass and radius yields a mean bulk density of 2.67 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.12 g⊕ (10.98 m/s²), and an escape velocity of 17.9 km/s.
In its orbital architecture around K2-183, K2-183 d completes one full revolution every 22.62 Earth days at a semi-major axis of 0.1527 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 73.4 km/s (compared to Earth's 29.8 km/s).
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 615 K (+342°C / +648°F) and receiving 31.66 S⊕ (~43,092 W/m²), K2-183 d orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star K2-183 is classified as a stellar host with an effective photospheric temperature of 5,482 K, a radius of 0.87 R☉, a mass of 0.9422 M☉, an estimated bolometric luminosity of 0.613 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.09 dex (metal-rich relative to the Sun). From Earth, K2-183 shines at apparent V-band magnitude 12.867 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The K2-183 system is a multi-planet architecture hosting 3 confirmed worlds, with K2-183 d sharing its stellar neighborhood alongside K2-183 b, K2-183 c.
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 | K2-183 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,482 K |
| Stellar Radius | 0.8700 R☉ |
| Stellar Mass | 0.9422 M☉ |
| Bolometric Luminosity | 0.613 L☉ |
| Metallicity [Fe/H] | 0.090 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 12.867 · G: 12.670 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.152700 AU |
| Orbital Period | 22.62 days |
| Mean Orbital Velocity | 73.4 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 89.9000° |
| Mean Bulk Density | 2.67 g/cm³ (17.9 km/s vesc) |
| Insolation Flux | 31.6618 S⊕ (~43,092 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1073.200 LY (329.041 pc) |