HD 50499 b
Astrophysical Synthesis & Habitability Characterization
HD 50499 b is a confirmed gas giant exoplanet orbiting the star HD 50499, located approximately 151 light-years (46.29 parsecs) from the Solar System. First announced in 2005 by W. M. Keck Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.5 Earth radii (1.2 Jupiter radii) and has a measured mass of 519.97 Earth masses (1.64 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.17 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2.85 g⊕ (27.95 m/s²), and an escape velocity of 69.4 km/s.
In its orbital architecture around HD 50499, HD 50499 b completes one full revolution every 2447.1 Earth days (6.7Julian years) at a semi-major axis of 3.833 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 17 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.266, swinging from 2.8134 AU at periapsis out to 4.8526 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 175 K (-98°C / -144°F) and an incident flux of 0.16 S⊕ (~220 W/m²), surface water and volatile species on HD 50499 b would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star HD 50499 is classified as a solar-type yellow star of spectral type G1 V with an effective photospheric temperature of 6,102 K, a radius of 1.351 R☉, a mass of 1.253 M☉, an estimated bolometric luminosity of 2.27 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.391 Gyr and a metallicity of [Fe/H] = 0.26 dex (metal-rich relative to the Sun). From Earth, HD 50499 shines at apparent V-band magnitude 7.21 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The HD 50499 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 50499 b sharing its stellar neighborhood alongside HD 50499 c.
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: W. M. Keck Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 50499 |
| Spectral Type | G1 V |
| Effective Temp (Teff) | 6,102 K |
| Stellar Radius | 1.3510 R☉ |
| Stellar Mass | 1.2530 M☉ |
| Bolometric Luminosity | 2.27 L☉ |
| Metallicity [Fe/H] | 0.260 dex |
| Stellar Age | 2.391 Gyr |
| Apparent Magnitude | V: 7.210 · G: 7.056 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 3.833000 AU |
| Orbital Period | 2447.1 days |
| Mean Orbital Velocity | 17 km/s |
| Orbital Eccentricity (e) | 0.26600 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.17 g/cm³ (69.4 km/s vesc) |
| Insolation Flux | 0.1619 S⊕ (~220 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 151.000 LY (46.285 pc) |