HD 89839 b
Astrophysical Synthesis & Habitability Characterization
HD 89839 b is a confirmed gas giant exoplanet orbiting the star HD 89839, located approximately 186.9 light-years (57.31 parsecs) from the Solar System. First announced in 2023 by Multiple Facilities using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.8 Earth radii (1.14 Jupiter radii) and has a measured mass of 1748.056 Earth masses (5.5 Jupiter masses). Combining its mass and radius yields a mean bulk density of 4.6 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 10.67 g⊕ (104.64 m/s²), and an escape velocity of 130.7 km/s.
In its orbital architecture around HD 89839, HD 89839 b completes one full revolution every 3391.2 Earth days (9.28Julian years) at a semi-major axis of 4.713 AU (corresponding to the middle-system regime between Mars at 1.52 AU and Jupiter at 5.20 AU). Its mean orbital velocity is approximately 15.1 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.185 carries the world between 3.8411 AU at periapsis and 5.5849 AU at apoapsis, driving measurable seasonal insolation cycles.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 159 K (-114°C / -173°F) and an incident flux of 0.11 S⊕ (~145 W/m²), surface water and volatile species on HD 89839 b would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star HD 89839 is classified as a warm F-type star of spectral type F7 V with an effective photospheric temperature of 6,314 K, a radius of 1.2859 R☉, a mass of 1.21 M☉, an estimated bolometric luminosity of 2.358 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.6 Gyr and a metallicity of [Fe/H] = 0.04 dex (near-solar heavy-element abundance). From Earth, HD 89839 shines at apparent V-band magnitude 7.64 (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 Facilities · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 89839 |
| Spectral Type | F7 V |
| Effective Temp (Teff) | 6,314 K |
| Stellar Radius | 1.2859 R☉ |
| Stellar Mass | 1.2100 M☉ |
| Bolometric Luminosity | 2.358 L☉ |
| Metallicity [Fe/H] | 0.040 dex |
| Stellar Age | 1.600 Gyr |
| Apparent Magnitude | V: 7.640 · G: 7.513 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 4.713000 AU |
| Orbital Period | 3391.2 days |
| Mean Orbital Velocity | 15.1 km/s |
| Orbital Eccentricity (e) | 0.18500 |
| Orbital Inclination (i) | 49.5000° |
| Mean Bulk Density | 4.6 g/cm³ (130.7 km/s vesc) |
| Insolation Flux | 0.1067 S⊕ (~145 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 186.900 LY (57.306 pc) |