HD 190984 b
Astrophysical Synthesis & Habitability Characterization
HD 190984 b is a confirmed gas giant exoplanet orbiting the star HD 190984, located approximately 483.3 light-years (148.19 parsecs) from the Solar System. First announced in 2009 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13 Earth radii (1.16 Jupiter radii) and has a measured mass of 1137.826 Earth masses (3.58 Jupiter masses). Combining its mass and radius yields a mean bulk density of 2.86 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 6.73 g⊕ (66 m/s²), and an escape velocity of 104.7 km/s.
In its orbital architecture around HD 190984, HD 190984 b completes one full revolution every 4885 Earth days (13.37Julian years) at a semi-major axis of 5.5 AU (a wide outer-system orbit beyond Jupiter's 5.20 AU distance in our Solar System). Its mean orbital velocity is approximately 12.2 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.57, swinging from 2.365 AU at periapsis out to 8.635 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 152 K (-121°C / -186°F) and an incident flux of 0.09 S⊕ (~121 W/m²), surface water and volatile species on HD 190984 b would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star HD 190984 is classified as a warm F-type star of spectral type F8 V with an effective photospheric temperature of 5,988 K, a radius of 1.53 R☉, a mass of 0.91 M☉, an estimated bolometric luminosity of 2.7 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.48 dex (metal-poor relative to the Sun). From Earth, HD 190984 shines at apparent V-band magnitude 8.76 (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: La Silla Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 190984 |
| Spectral Type | F8 V |
| Effective Temp (Teff) | 5,988 K |
| Stellar Radius | 1.5300 R☉ |
| Stellar Mass | 0.9100 M☉ |
| Bolometric Luminosity | 2.7 L☉ |
| Metallicity [Fe/H] | -0.480 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 8.760 · G: 8.611 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 5.500000 AU |
| Orbital Period | 4885 days |
| Mean Orbital Velocity | 12.2 km/s |
| Orbital Eccentricity (e) | 0.57000 |
| Orbital Inclination (i) | 64.0000° |
| Mean Bulk Density | 2.86 g/cm³ (104.7 km/s vesc) |
| Insolation Flux | 0.0890 S⊕ (~121 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 483.300 LY (148.187 pc) |