HD 30177 c
Astrophysical Synthesis & Habitability Characterization
HD 30177 c is a confirmed gas giant exoplanet orbiting the star HD 30177, located approximately 181.3 light-years (55.59 parsecs) from the Solar System. First announced in 2016 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.9 Earth radii (1.15 Jupiter radii) and has a measured mass of 1484.259 Earth masses (4.67 Jupiter masses). Combining its mass and radius yields a mean bulk density of 3.81 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 8.92 g⊕ (87.48 m/s²), and an escape velocity of 120 km/s.
In its orbital architecture around HD 30177, HD 30177 c completes one full revolution every 11320 Earth days (30.99Julian years) at a semi-major axis of 9.9 AU (a wide outer-system orbit beyond Jupiter's 5.20 AU distance in our Solar System). Its mean orbital velocity is approximately 9.5 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.21 carries the world between 7.821 AU at periapsis and 11.979 AU at apoapsis, driving measurable seasonal insolation cycles.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 88 K (-185°C / -301°F) and an incident flux of 0.01 S⊕ (~17 W/m²), surface water and volatile species on HD 30177 c would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star HD 30177 is classified as a solar-type yellow star of spectral type G8 V with an effective photospheric temperature of 5,680 K, a radius of 1.019 R☉, a mass of 0.98 M☉, an estimated bolometric luminosity of 0.97 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.55 Gyr and a metallicity of [Fe/H] = 0.43 dex (metal-rich relative to the Sun). From Earth, HD 30177 shines at apparent V-band magnitude 8.41 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The HD 30177 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 30177 c sharing its stellar neighborhood alongside HD 30177 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 30177 |
| Spectral Type | G8 V |
| Effective Temp (Teff) | 5,680 K |
| Stellar Radius | 1.0190 R☉ |
| Stellar Mass | 0.9800 M☉ |
| Bolometric Luminosity | 0.97 L☉ |
| Metallicity [Fe/H] | 0.430 dex |
| Stellar Age | 3.550 Gyr |
| Apparent Magnitude | V: 8.410 · G: 8.215 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 9.900000 AU |
| Orbital Period | 11320 days |
| Mean Orbital Velocity | 9.5 km/s |
| Orbital Eccentricity (e) | 0.21000 |
| Orbital Inclination (i) | 72.7000° |
| Mean Bulk Density | 3.81 g/cm³ (120 km/s vesc) |
| Insolation Flux | 0.0124 S⊕ (~17 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 181.300 LY (55.587 pc) |