16 Cyg B b
Astrophysical Synthesis & Habitability Characterization
16 Cyg B b is a confirmed gas giant exoplanet orbiting the star 16 Cyg B, located approximately 68.9 light-years (21.14 parsecs) from the Solar System. First announced in 1996 by Multiple Observatories 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 565.737 Earth masses (1.78 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.27 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 3.1 g⊕ (30.4 m/s²), and an escape velocity of 72.4 km/s.
In its orbital architecture around 16 Cyg B, 16 Cyg B b completes one full revolution every 798.5 Earth days (2.19Julian years) at a semi-major axis of 1.66 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 22.6 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.68, swinging from 0.5312 AU at periapsis out to 2.7888 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 13.500 R⊕, 16 Cyg B b exceeds the empirical ~1.8–2.2 R⊕ Fulton radius valley threshold, indicating a substantial hydrogen-helium or supercritical volatile envelope without a conventional solid terrestrial surface.
The host star 16 Cyg B is classified as a solar-type yellow star of spectral type G3 V with an effective photospheric temperature of 5,750 K, a radius of 1.13 R☉, a mass of 1.08 M☉, an estimated bolometric luminosity of 1.252 L☉. Stellar evolution modeling indicates an estimated stellar age of 7.4 Gyr and a metallicity of [Fe/H] = 0.06 dex (metal-rich relative to the Sun). From Earth, 16 Cyg B shines at apparent V-band magnitude 6.215 (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: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | 16 Cyg B |
| Spectral Type | G3 V |
| Effective Temp (Teff) | 5,750 K |
| Stellar Radius | 1.1300 R☉ |
| Stellar Mass | 1.0800 M☉ |
| Bolometric Luminosity | 1.252 L☉ |
| Metallicity [Fe/H] | 0.060 dex |
| Stellar Age | 7.400 Gyr |
| Apparent Magnitude | V: 6.215 · G: 6.064 |
| System Architecture | 3 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.660000 AU |
| Orbital Period | 798.5 days |
| Mean Orbital Velocity | 22.6 km/s |
| Orbital Eccentricity (e) | 0.68000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.27 g/cm³ (72.4 km/s vesc) |
| Insolation Flux | 0.4540 S⊕ (~618 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 68.900 LY (21.140 pc) |