HD 189567 c
Astrophysical Synthesis & Habitability Characterization
HD 189567 c is a confirmed sub-neptune exoplanet orbiting the star HD 189567, located approximately 58.4 light-years (17.91 parsecs) from the Solar System. First announced in 2021 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 2.54 Earth radii and has a measured mass of 7 Earth masses. Combining its mass and radius yields a mean bulk density of 2.36 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.09 g⊕ (10.69 m/s²), and an escape velocity of 18.6 km/s.
In its orbital architecture around HD 189567, HD 189567 c completes one full revolution every 33.688 Earth days at a semi-major axis of 0.197 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 63.6 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.16 carries the world between 0.1655 AU at periapsis and 0.2285 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 634 K (+361°C / +682°F) and receiving 54.37 S⊕ (~73,996 W/m²), HD 189567 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 189567 is classified as a solar-type yellow star of spectral type G3 V with an effective photospheric temperature of 5,726 K, a radius of 1.04 R☉, a mass of 0.83 M☉, an estimated bolometric luminosity of 1.043 L☉. Stellar evolution modeling indicates an estimated stellar age of 11 Gyr and a metallicity of [Fe/H] = -0.24 dex (metal-poor relative to the Sun). From Earth, HD 189567 shines at apparent V-band magnitude 6.074 (visible to the unaided human eye under dark skies) in the Southern celestial hemisphere. The HD 189567 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 189567 c sharing its stellar neighborhood alongside HD 189567 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: La Silla Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 189567 |
| Spectral Type | G3 V |
| Effective Temp (Teff) | 5,726 K |
| Stellar Radius | 1.0400 R☉ |
| Stellar Mass | 0.8300 M☉ |
| Bolometric Luminosity | 1.043 L☉ |
| Metallicity [Fe/H] | -0.240 dex |
| Stellar Age | 11.000 Gyr |
| Apparent Magnitude | V: 6.074 · G: 5.910 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.197000 AU |
| Orbital Period | 33.688 days |
| Mean Orbital Velocity | 63.6 km/s |
| Orbital Eccentricity (e) | 0.16000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 2.36 g/cm³ (18.6 km/s vesc) |
| Insolation Flux | 54.3688 S⊕ (~73,996 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 58.400 LY (17.906 pc) |