bet UMi b
Astrophysical Synthesis & Habitability Characterization
bet UMi b is a confirmed gas giant exoplanet orbiting the star bet UMi, located approximately 126.5 light-years (38.78 parsecs) from the Solar System. First announced in 2014 by Bohyunsan Optical Astronomical Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.7 Earth radii (1.13 Jupiter radii) and has a measured mass of 1938.7 Earth masses (6.1 Jupiter masses). Combining its mass and radius yields a mean bulk density of 5.22 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 12.02 g⊕ (117.88 m/s²), and an escape velocity of 138.2 km/s.
In its orbital architecture around bet UMi, bet UMi b completes one full revolution every 522.3 Earth days (1.43Julian years) at a semi-major axis of 1.4 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 29.2 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.19 carries the world between 1.134 AU at periapsis and 1.666 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1041 K (+768°C / +1414°F) and receiving 274.00 S⊕ (~372,908 W/m²), bet UMi b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star bet UMi is classified as an orange K-type star of spectral type K4 III with an effective photospheric temperature of 4,126 K, a radius of 38.3 R☉, a mass of 1.4 M☉, an estimated bolometric luminosity of 381.421 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.95 Gyr and a metallicity of [Fe/H] = -0.27 dex (metal-poor relative to the Sun). From Earth, bet UMi shines at apparent V-band magnitude 2.057 (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: Bohyunsan Optical Astronomical Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | bet UMi |
| Spectral Type | K4 III |
| Effective Temp (Teff) | 4,126 K |
| Stellar Radius | 38.3000 R☉ |
| Stellar Mass | 1.4000 M☉ |
| Bolometric Luminosity | 381.421 L☉ |
| Metallicity [Fe/H] | -0.270 dex |
| Stellar Age | 2.950 Gyr |
| Apparent Magnitude | V: 2.057 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.400000 AU |
| Orbital Period | 522.3 days |
| Mean Orbital Velocity | 29.2 km/s |
| Orbital Eccentricity (e) | 0.19000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 5.22 g/cm³ (138.2 km/s vesc) |
| Insolation Flux | 273.9958 S⊕ (~372,908 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 126.500 LY (38.775 pc) |