55 Cnc f
Astrophysical Synthesis & Habitability Characterization
55 Cnc f is a confirmed gas giant exoplanet orbiting the star 55 Cnc, located approximately 41 light-years (12.59 parsecs) from the Solar System. First announced in 2007 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 7.59 Earth radii (0.68 Jupiter radii) and has a measured mass of 44.812 Earth masses (0.14 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.57 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.78 g⊕ (7.65 m/s²), and an escape velocity of 27.2 km/s.
In its orbital architecture around 55 Cnc, 55 Cnc f completes one full revolution every 260.58 Earth days at a semi-major axis of 0.802 AU (comparable to the inner terrestrial zone between Venus, Earth at 1.00 AU, and Mars at 1.52 AU). Its mean orbital velocity is approximately 33.5 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.063 carries the world between 0.7515 AU at periapsis and 0.8525 AU at apoapsis, driving measurable seasonal insolation cycles.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 7.590 R⊕, 55 Cnc f 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 55 Cnc is classified as a solar-type yellow star of spectral type G8 V with an effective photospheric temperature of 5,198 K, a radius of 0.98 R☉, a mass of 1.015 M☉, an estimated bolometric luminosity of 0.629 L☉. Stellar evolution modeling indicates an estimated stellar age of 10 Gyr and a metallicity of [Fe/H] = 0.39 dex (metal-rich relative to the Sun). From Earth, 55 Cnc shines at apparent V-band magnitude 5.951 (visible to the unaided human eye under dark skies) in the Northern celestial hemisphere. The 55 Cnc system is a multi-planet architecture hosting 5 confirmed worlds, with 55 Cnc f sharing its stellar neighborhood alongside 55 Cnc e, 55 Cnc b, 55 Cnc c, 55 Cnc d.
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 | 55 Cnc |
| Spectral Type | G8 V |
| Effective Temp (Teff) | 5,198 K |
| Stellar Radius | 0.9800 R☉ |
| Stellar Mass | 1.0150 M☉ |
| Bolometric Luminosity | 0.629 L☉ |
| Metallicity [Fe/H] | 0.390 dex |
| Stellar Age | 10.000 Gyr |
| Apparent Magnitude | V: 5.951 · G: 5.730 |
| System Architecture | 2 Stars, 7 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.802000 AU |
| Orbital Period | 260.58 days |
| Mean Orbital Velocity | 33.5 km/s |
| Orbital Eccentricity (e) | 0.06300 |
| Orbital Inclination (i) | 89.7300° |
| Mean Bulk Density | 0.57 g/cm³ (27.2 km/s vesc) |
| Insolation Flux | 0.9879 S⊕ (~1,345 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 41.000 LY (12.586 pc) |