6 Lyn b
Astrophysical Synthesis & Habitability Characterization
6 Lyn b is a confirmed gas giant exoplanet orbiting the star 6 Lyn, located approximately 178.3 light-years (54.66 parsecs) from the Solar System. First announced in 2008 by Okayama Astrophysical Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.4 Earth radii (1.2 Jupiter radii) and has a measured mass of 597.835 Earth masses (1.88 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.37 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 3.33 g⊕ (32.66 m/s²), and an escape velocity of 74.7 km/s.
In its orbital architecture around 6 Lyn, 6 Lyn b completes one full revolution every 919.86 Earth days (2.52Julian years) at a semi-major axis of 2.028 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 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.042 (ranging from 1.9428 AU at periapsis to 2.1132 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 372 K (+99°C / +210°F) and receiving 3.19 S⊕ (~4,348 W/m²), 6 Lyn b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star 6 Lyn is classified as an orange K-type star of spectral type K0 IV with an effective photospheric temperature of 4,941 K, a radius of 4.94 R☉, a mass of 1.32 M☉, an estimated bolometric luminosity of 13.05 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.353 Gyr and a metallicity of [Fe/H] = -0.17 dex (metal-poor relative to the Sun). From Earth, 6 Lyn shines at apparent V-band magnitude 5.873 (visible to the unaided human eye under dark skies) 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: Okayama Astrophysical Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | 6 Lyn |
| Spectral Type | K0 IV |
| Effective Temp (Teff) | 4,941 K |
| Stellar Radius | 4.9400 R☉ |
| Stellar Mass | 1.3200 M☉ |
| Bolometric Luminosity | 13.05 L☉ |
| Metallicity [Fe/H] | -0.170 dex |
| Stellar Age | 2.353 Gyr |
| Apparent Magnitude | V: 5.873 · G: 5.607 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 2.028000 AU |
| Orbital Period | 919.86 days |
| Mean Orbital Velocity | 24 km/s |
| Orbital Eccentricity (e) | 0.04200 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.37 g/cm³ (74.7 km/s vesc) |
| Insolation Flux | 3.1949 S⊕ (~4,348 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 178.300 LY (54.660 pc) |