HD 18143 c
Astrophysical Synthesis & Habitability Characterization
HD 18143 c is a confirmed gas giant exoplanet orbiting the star HD 18143, located approximately 73.5 light-years (22.52 parsecs) from the Solar System. First announced in 2022 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.5 Earth radii (1.12 Jupiter radii) and has a measured mass of 3177.648 Earth masses (10 Jupiter masses). Combining its mass and radius yields a mean bulk density of 8.97 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 20.34 g⊕ (199.47 m/s²), and an escape velocity of 178.3 km/s.
In its orbital architecture around HD 18143, HD 18143 c completes one full revolution every 28982.418 Earth days (79.35Julian years) at a semi-major axis of 17.53 AU (a wide outer-system orbit beyond Jupiter's 5.20 AU distance in our Solar System). Its mean orbital velocity is approximately 6.6 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.194 carries the world between 14.1292 AU at periapsis and 20.9308 AU at apoapsis, driving measurable seasonal insolation cycles.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 55 K (-218°C / -360°F) and an incident flux of 0.00 S⊕ (~2 W/m²), surface water and volatile species on HD 18143 c would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star HD 18143 is classified as an orange K-type star of spectral type K2 with an effective photospheric temperature of 5,078 K, a radius of 0.87 R☉, a mass of 0.85 M☉, an estimated bolometric luminosity of 0.452 L☉. Stellar evolution modeling indicates an estimated stellar age of 9.4 Gyr and a metallicity of [Fe/H] = 0.28 dex (metal-rich relative to the Sun). From Earth, HD 18143 shines at apparent V-band magnitude 7.518 (accessible to binoculars and small amateur telescopes) in the Northern celestial hemisphere. The HD 18143 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 18143 c sharing its stellar neighborhood alongside HD 18143 b.
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: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 18143 |
| Spectral Type | K2 |
| Effective Temp (Teff) | 5,078 K |
| Stellar Radius | 0.8700 R☉ |
| Stellar Mass | 0.8500 M☉ |
| Bolometric Luminosity | 0.452 L☉ |
| Metallicity [Fe/H] | 0.280 dex |
| Stellar Age | 9.400 Gyr |
| Apparent Magnitude | V: 7.518 · G: 7.332 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 17.530000 AU |
| Orbital Period | 28982.418 days |
| Mean Orbital Velocity | 6.6 km/s |
| Orbital Eccentricity (e) | 0.19400 |
| Orbital Inclination (i) | 35.9800° |
| Mean Bulk Density | 8.97 g/cm³ (178.3 km/s vesc) |
| Insolation Flux | 0.0016 S⊕ (~2 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 73.500 LY (22.524 pc) |