HD 188641 b
Astrophysical Synthesis & Habitability Characterization
HD 188641 b is a confirmed gas giant exoplanet orbiting the star HD 188641, located approximately 209.8 light-years (64.34 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 11.9 Earth radii (1.06 Jupiter radii) and has a measured mass of 9333.031 Earth masses (29.36 Jupiter masses). Combining its mass and radius yields a mean bulk density of 30.54 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 65.91 g⊕ (646.36 m/s²), and an escape velocity of 313.3 km/s.
In its orbital architecture around HD 188641, HD 188641 b completes one full revolution every 14583.81 Earth days (39.93Julian years) at a semi-major axis of 12.027 AU (a wide outer-system orbit beyond Jupiter's 5.20 AU distance in our Solar System). Its mean orbital velocity is approximately 9 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.034 (ranging from 11.6181 AU at periapsis to 12.4359 AU at apoapsis), the planet experiences minimal orbital distance variation.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 114 K (-159°C / -254°F) and an incident flux of 0.03 S⊕ (~39 W/m²), surface water and volatile species on HD 188641 b would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star HD 188641 is classified as a stellar host with an effective photospheric temperature of 5,897 K, a radius of 1.9449 R☉, a mass of 1.07 M☉, an estimated bolometric luminosity of 4.104 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.08 dex (near-solar heavy-element abundance). From Earth, HD 188641 shines at apparent V-band magnitude 7.34 (accessible to binoculars and small amateur telescopes) in the Southern 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: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 188641 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,897 K |
| Stellar Radius | 1.9449 R☉ |
| Stellar Mass | 1.0700 M☉ |
| Bolometric Luminosity | 4.104 L☉ |
| Metallicity [Fe/H] | -0.080 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 7.340 · G: 7.178 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 12.027000 AU |
| Orbital Period | 14583.81 days |
| Mean Orbital Velocity | 9 km/s |
| Orbital Eccentricity (e) | 0.03400 |
| Orbital Inclination (i) | 49.2450° |
| Mean Bulk Density | 30.54 g/cm³ (313.3 km/s vesc) |
| Insolation Flux | 0.0285 S⊕ (~39 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 209.800 LY (64.340 pc) |