ROXs 12 b
Astrophysical Synthesis & Habitability Characterization
ROXs 12 b is a confirmed gas giant exoplanet orbiting the star ROXs 12, located approximately 445.7 light-years (136.65 parsecs) from the Solar System. First announced in 2013 by W. M. Keck Observatory using the Imaging detection technique (resolved directly via high-contrast coronagraphic or interferometric imaging), this world measures 12.2 Earth radii (1.09 Jupiter radii) and has a measured mass of 5085 Earth masses (16 Jupiter masses). Combining its mass and radius yields a mean bulk density of 15.44 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 34.16 g⊕ (335 m/s²), and an escape velocity of 228.4 km/s.
The planet follows a highly eccentric trajectory (e = 0.83, swinging from 35.7 AU at periapsis out to 384.3 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 13 K (-260°C / -436°F), surface water and volatile species on ROXs 12 b would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star ROXs 12 is classified as a low-mass red dwarf of spectral type M0 with an effective photospheric temperature of 3,850 K, a radius of 1.0663 R☉, a mass of 0.87 M☉, an estimated bolometric luminosity of 0.224 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.008 Gyr and a metallicity of [Fe/H] = 0.14 dex (metal-rich relative to the Sun). From Earth, ROXs 12 shines at apparent V-band magnitude 14.763 (faint and requiring research-grade or CCD telescopic photometry) 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: W. M. Keck Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | ROXs 12 |
| Spectral Type | M0 |
| Effective Temp (Teff) | 3,850 K |
| Stellar Radius | 1.0663 R☉ |
| Stellar Mass | 0.8700 M☉ |
| Bolometric Luminosity | 0.224 L☉ |
| Metallicity [Fe/H] | 0.140 dex |
| Stellar Age | 0.008 Gyr |
| Apparent Magnitude | V: 14.763 · G: 13.266 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 210.000000 AU |
| Orbital Period | — |
| Orbital Eccentricity (e) | 0.83000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 15.44 g/cm³ (228.4 km/s vesc) |
| Insolation Flux | 0.0000 S⊕ |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 445.700 LY (136.650 pc) |