HD 82886 b
Astrophysical Synthesis & Habitability Characterization
HD 82886 b is a confirmed gas giant exoplanet orbiting the star HD 82886, located approximately 414.4 light-years (127.06 parsecs) from the Solar System. First announced in 2011 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 13.3 Earth radii (1.19 Jupiter radii) and has a measured mass of 740.544 Earth masses (2.33 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.74 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 4.19 g⊕ (41.09 m/s²), and an escape velocity of 83.5 km/s.
In its orbital architecture around HD 82886, HD 82886 b completes one full revolution every 705 Earth days (1.93Julian years) at a semi-major axis of 1.58 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 24.4 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.07 carries the world between 1.4694 AU at periapsis and 1.6906 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 436 K (+163°C / +325°F) and receiving 5.57 S⊕ (~7,578 W/m²), HD 82886 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 82886 is classified as a solar-type yellow star of spectral type G0 with an effective photospheric temperature of 4,953 K, a radius of 5.26 R☉, a mass of 2.53 M☉, an estimated bolometric luminosity of 14.939 L☉. Stellar evolution modeling indicates an estimated stellar age of 7 Gyr and a metallicity of [Fe/H] = -0.31 dex (metal-poor relative to the Sun). From Earth, HD 82886 shines at apparent V-band magnitude 7.62 (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: W. M. Keck Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 82886 |
| Spectral Type | G0 |
| Effective Temp (Teff) | 4,953 K |
| Stellar Radius | 5.2600 R☉ |
| Stellar Mass | 2.5300 M☉ |
| Bolometric Luminosity | 14.939 L☉ |
| Metallicity [Fe/H] | -0.310 dex |
| Stellar Age | 7.000 Gyr |
| Apparent Magnitude | V: 7.620 · G: 7.381 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.580000 AU |
| Orbital Period | 705 days |
| Mean Orbital Velocity | 24.4 km/s |
| Orbital Eccentricity (e) | 0.07000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.74 g/cm³ (83.5 km/s vesc) |
| Insolation Flux | 5.5680 S⊕ (~7,578 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 414.400 LY (127.061 pc) |