nu Oph c
Astrophysical Synthesis & Habitability Characterization
nu Oph c is a confirmed gas giant exoplanet orbiting the star nu Oph, located approximately 150.7 light-years (46.21 parsecs) from the Solar System. First announced in 2012 by Okayama Astrophysical Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12 Earth radii (1.07 Jupiter radii) and has a measured mass of 7838.323 Earth masses (24.66 Jupiter masses). Combining its mass and radius yields a mean bulk density of 25.01 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 54.43 g⊕ (533.78 m/s²), and an escape velocity of 285.9 km/s.
In its orbital architecture around nu Oph, nu Oph c completes one full revolution every 3180.6 Earth days (8.71Julian years) at a semi-major axis of 5.829 AU (a wide outer-system orbit beyond Jupiter's 5.20 AU distance in our Solar System). Its mean orbital velocity is approximately 19.9 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.179 carries the world between 4.7856 AU at periapsis and 6.8724 AU at apoapsis, driving measurable seasonal insolation cycles.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 12.000 R⊕, nu Oph c 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 nu Oph is classified as an orange K-type star of spectral type K0 III with an effective photospheric temperature of 4,887 K, a radius of 12.24 R☉, a mass of 2.61 M☉, an estimated bolometric luminosity of 76.669 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.65 Gyr and a metallicity of [Fe/H] = 0.1 dex (metal-rich relative to the Sun). From Earth, nu Oph shines at apparent V-band magnitude 3.312 (visible to the unaided human eye under dark skies) in the Southern celestial hemisphere. The nu Oph system is a multi-planet architecture hosting 2 confirmed worlds, with nu Oph c sharing its stellar neighborhood alongside nu Oph b.
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 | nu Oph |
| Spectral Type | K0 III |
| Effective Temp (Teff) | 4,887 K |
| Stellar Radius | 12.2400 R☉ |
| Stellar Mass | 2.6100 M☉ |
| Bolometric Luminosity | 76.669 L☉ |
| Metallicity [Fe/H] | 0.100 dex |
| Stellar Age | 0.650 Gyr |
| Apparent Magnitude | V: 3.312 · G: 3.097 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 5.829000 AU |
| Orbital Period | 3180.6 days |
| Mean Orbital Velocity | 19.9 km/s |
| Orbital Eccentricity (e) | 0.17900 |
| Orbital Inclination (i) | 90.0000° |
| Mean Bulk Density | 25.01 g/cm³ (285.9 km/s vesc) |
| Insolation Flux | 2.3098 S⊕ (~3,144 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 150.700 LY (46.211 pc) |