HD 43197 c
Astrophysical Synthesis & Habitability Characterization
HD 43197 c is a confirmed gas giant exoplanet orbiting the star HD 43197, located approximately 203.6 light-years (62.41 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 12.6 Earth radii (1.12 Jupiter radii) and has a measured mass of 2500.674 Earth masses (7.87 Jupiter masses). Combining its mass and radius yields a mean bulk density of 6.89 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 15.75 g⊕ (154.45 m/s²), and an escape velocity of 157.6 km/s.
In its orbital architecture around HD 43197, HD 43197 c completes one full revolution every 9295.974 Earth days (25.45Julian years) at a semi-major axis of 8.54 AU (a wide outer-system orbit beyond Jupiter's 5.20 AU distance in our Solar System). Its mean orbital velocity is approximately 10 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.149 carries the world between 7.2675 AU at periapsis and 9.8125 AU at apoapsis, driving measurable seasonal insolation cycles.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 91 K (-182°C / -296°F) and an incident flux of 0.01 S⊕ (~14 W/m²), surface water and volatile species on HD 43197 c would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star HD 43197 is classified as a solar-type yellow star of spectral type G8 V with an effective photospheric temperature of 5,508 K, a radius of 1 R☉, a mass of 0.96 M☉, an estimated bolometric luminosity of 0.826 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.4 dex (metal-rich relative to the Sun). From Earth, HD 43197 shines at apparent V-band magnitude 8.98 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The HD 43197 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 43197 c sharing its stellar neighborhood alongside HD 43197 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 43197 |
| Spectral Type | G8 V |
| Effective Temp (Teff) | 5,508 K |
| Stellar Radius | 1.0000 R☉ |
| Stellar Mass | 0.9600 M☉ |
| Bolometric Luminosity | 0.826 L☉ |
| Metallicity [Fe/H] | 0.400 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 8.980 · G: 8.772 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 8.540000 AU |
| Orbital Period | 9295.974 days |
| Mean Orbital Velocity | 10 km/s |
| Orbital Eccentricity (e) | 0.14900 |
| Orbital Inclination (i) | 11.4200° |
| Mean Bulk Density | 6.89 g/cm³ (157.6 km/s vesc) |
| Insolation Flux | 0.0100 S⊕ (~14 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 203.600 LY (62.411 pc) |