HD 13189 b
Astrophysical Synthesis & Habitability Characterization
HD 13189 b is a confirmed gas giant exoplanet orbiting the star HD 13189, located approximately 1623.7 light-years (497.82 parsecs) from the Solar System. First announced in 2005 by Thueringer Landessternwarte Tautenburg using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.4 Earth radii (1.11 Jupiter radii) and has a measured mass of 3480.239 Earth masses (10.95 Jupiter masses). Combining its mass and radius yields a mean bulk density of 10.06 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 22.63 g⊕ (221.92 m/s²), and an escape velocity of 187.4 km/s.
In its orbital architecture around HD 13189, HD 13189 b completes one full revolution every 471.6 Earth days (1.29Julian years) at a semi-major axis of 1.25 AU (comparable to the inner terrestrial zone between Venus, Earth at 1.00 AU, and Mars at 1.52 AU). Its mean orbital velocity is approximately 28.8 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.27, swinging from 0.9125 AU at periapsis out to 1.5875 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1116 K (+843°C / +1549°F) and receiving 277.05 S⊕ (~377,069 W/m²), HD 13189 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 13189 is classified as an orange K-type star of spectral type K2 with an effective photospheric temperature of 4,175 K, a radius of 38.41 R☉, a mass of 2.24 M☉, an estimated bolometric luminosity of 402.165 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.37 dex (metal-poor relative to the Sun). From Earth, HD 13189 shines at apparent V-band magnitude 7.57 (accessible to binoculars and small amateur telescopes) in the Northern celestial hemisphere.
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: Thueringer Landessternwarte Tautenburg · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 13189 |
| Spectral Type | K2 |
| Effective Temp (Teff) | 4,175 K |
| Stellar Radius | 38.4100 R☉ |
| Stellar Mass | 2.2400 M☉ |
| Bolometric Luminosity | 402.165 L☉ |
| Metallicity [Fe/H] | -0.370 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 7.570 · G: 7.017 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.250000 AU |
| Orbital Period | 471.6 days |
| Mean Orbital Velocity | 28.8 km/s |
| Orbital Eccentricity (e) | 0.27000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 10.06 g/cm³ (187.4 km/s vesc) |
| Insolation Flux | 277.0528 S⊕ (~377,069 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1623.700 LY (497.823 pc) |