HD 88133 b
Astrophysical Synthesis & Habitability Characterization
HD 88133 b is a confirmed gas giant exoplanet orbiting the star HD 88133, located approximately 240.1 light-years (73.61 parsecs) from the Solar System. First announced in 2004 by W. M. Keck Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.8 Earth radii (1.23 Jupiter radii) and has a measured mass of 324.187 Earth masses (1.02 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.68 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.7 g⊕ (16.67 m/s²), and an escape velocity of 54.2 km/s.
In its orbital architecture around HD 88133, HD 88133 b completes one full revolution every 3.415 Earth days at a semi-major axis of 0.0479 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 152.6 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.031 (ranging from 0.0464 AU at periapsis to 0.0494 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1762 K (+1489°C / +2712°F) and receiving 1,368.09 S⊕ (~1,861,967 W/m²), HD 88133 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 88133 is classified as a solar-type yellow star of spectral type G5 with an effective photospheric temperature of 5,392 K, a radius of 2.2 R☉, a mass of 1.26 M☉, an estimated bolometric luminosity of 3.671 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.37 Gyr and a metallicity of [Fe/H] = 0.34 dex (metal-rich relative to the Sun). From Earth, HD 88133 shines at apparent V-band magnitude 8.019 (accessible to binoculars and small amateur telescopes) 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: W. M. Keck Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 88133 |
| Spectral Type | G5 |
| Effective Temp (Teff) | 5,392 K |
| Stellar Radius | 2.2000 R☉ |
| Stellar Mass | 1.2600 M☉ |
| Bolometric Luminosity | 3.671 L☉ |
| Metallicity [Fe/H] | 0.340 dex |
| Stellar Age | 5.370 Gyr |
| Apparent Magnitude | V: 8.019 · G: 7.810 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.047900 AU |
| Orbital Period | 3.415 days |
| Mean Orbital Velocity | 152.6 km/s |
| Orbital Eccentricity (e) | 0.03100 |
| Orbital Inclination (i) | 15.0000° |
| Mean Bulk Density | 0.68 g/cm³ (54.2 km/s vesc) |
| Insolation Flux | 1368.0872 S⊕ (~1,861,967 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 240.100 LY (73.612 pc) |