nu Oct A b
Astrophysical Synthesis & Habitability Characterization
nu Oct A b is a confirmed gas giant exoplanet orbiting the star nu Oct A, located approximately 69.1 light-years (21.2 parsecs) from the Solar System. First announced in 2016 by University of Canterbury Mt John 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 696.044 Earth masses (2.19 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.63 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 3.93 g⊕ (38.54 m/s²), and an escape velocity of 80.9 km/s.
In its orbital architecture around nu Oct A, nu Oct A b completes one full revolution every 402.4 Earth days (1.1Julian years) at a semi-major axis of 1.24 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 = 0.195 carries the world between 0.9982 AU at periapsis and 1.4818 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 477 K (+204°C / +399°F) and receiving 8.58 S⊕ (~11,684 W/m²), nu Oct A b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star nu Oct A is classified as an orange K-type star of spectral type K1 IV with an effective photospheric temperature of 4,910 K, a radius of 5.04 R☉, a mass of 1.57 M☉, an estimated bolometric luminosity of 13.246 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.7 Gyr and a metallicity of [Fe/H] = 0.18 dex (metal-rich relative to the Sun). From Earth, nu Oct A shines at apparent V-band magnitude 3.73 (visible to the unaided human eye under dark skies) in the Southern 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: University of Canterbury Mt John Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | nu Oct A |
| Spectral Type | K1 IV |
| Effective Temp (Teff) | 4,910 K |
| Stellar Radius | 5.0400 R☉ |
| Stellar Mass | 1.5700 M☉ |
| Bolometric Luminosity | 13.246 L☉ |
| Metallicity [Fe/H] | 0.180 dex |
| Stellar Age | 2.700 Gyr |
| Apparent Magnitude | V: 3.730 · G: 3.442 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.240000 AU |
| Orbital Period | 402.4 days |
| Mean Orbital Velocity | 33.5 km/s |
| Orbital Eccentricity (e) | 0.19500 |
| Orbital Inclination (i) | 108.2000° |
| Mean Bulk Density | 1.63 g/cm³ (80.9 km/s vesc) |
| Insolation Flux | 8.5848 S⊕ (~11,684 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 69.100 LY (21.200 pc) |