omi UMa b
Astrophysical Synthesis & Habitability Characterization
omi UMa b is a confirmed gas giant exoplanet orbiting the star omi UMa, located approximately 179.1 light-years (54.92 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 13 Earth radii (1.16 Jupiter radii) and has a measured mass of 1160.392 Earth masses (3.65 Jupiter masses). Combining its mass and radius yields a mean bulk density of 2.91 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 6.87 g⊕ (67.37 m/s²), and an escape velocity of 105.7 km/s.
In its orbital architecture around omi UMa, omi UMa b completes one full revolution every 1569.81 Earth days (4.3Julian years) at a semi-major axis of 3.691 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 25.6 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.149 carries the world between 3.141 AU at periapsis and 4.241 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 474 K (+201°C / +394°F) and receiving 8.48 S⊕ (~11,541 W/m²), omi UMa b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star omi UMa is classified as a solar-type yellow star of spectral type G4 II-III with an effective photospheric temperature of 5,075 K, a radius of 13.84 R☉, a mass of 2.72 M☉, an estimated bolometric luminosity of 114 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.16 dex (metal-poor relative to the Sun). From Earth, omi UMa shines at apparent V-band magnitude 3.352 (visible to the unaided human eye under dark skies) 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: Okayama Astrophysical Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | omi UMa |
| Spectral Type | G4 II-III |
| Effective Temp (Teff) | 5,075 K |
| Stellar Radius | 13.8400 R☉ |
| Stellar Mass | 2.7200 M☉ |
| Bolometric Luminosity | 114 L☉ |
| Metallicity [Fe/H] | -0.160 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 3.352 · G: 3.144 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 3.691000 AU |
| Orbital Period | 1569.81 days |
| Mean Orbital Velocity | 25.6 km/s |
| Orbital Eccentricity (e) | 0.14900 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 2.91 g/cm³ (105.7 km/s vesc) |
| Insolation Flux | 8.4795 S⊕ (~11,541 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 179.100 LY (54.915 pc) |