HD 33283 b
Astrophysical Synthesis & Habitability Characterization
HD 33283 b is a confirmed gas giant exoplanet orbiting the star HD 33283, located approximately 293.1 light-years (89.86 parsecs) from the Solar System. First announced in 2006 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 12.5 Earth radii (1.12 Jupiter radii) and has a measured mass of 104.566 Earth masses (0.33 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.3 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.67 g⊕ (6.57 m/s²), and an escape velocity of 32.4 km/s.
In its orbital architecture around HD 33283, HD 33283 b completes one full revolution every 18.199 Earth days at a semi-major axis of 0.1508 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 90.1 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.399, swinging from 0.0906 AU at periapsis out to 0.211 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1034 K (+761°C / +1402°F) and receiving 191.95 S⊕ (~261,250 W/m²), HD 33283 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 33283 is classified as a solar-type yellow star of spectral type G3/G5 V with an effective photospheric temperature of 5,935 K, a radius of 1.97 R☉, a mass of 1.38 M☉, an estimated bolometric luminosity of 4.32 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.63 Gyr and a metallicity of [Fe/H] = 0.35 dex (metal-rich relative to the Sun). From Earth, HD 33283 shines at apparent V-band magnitude 8.05 (accessible to binoculars and small amateur telescopes) 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 | HD 33283 |
| Spectral Type | G3/G5 V |
| Effective Temp (Teff) | 5,935 K |
| Stellar Radius | 1.9700 R☉ |
| Stellar Mass | 1.3800 M☉ |
| Bolometric Luminosity | 4.32 L☉ |
| Metallicity [Fe/H] | 0.350 dex |
| Stellar Age | 3.630 Gyr |
| Apparent Magnitude | V: 8.050 · G: 7.899 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.150800 AU |
| Orbital Period | 18.199 days |
| Mean Orbital Velocity | 90.1 km/s |
| Orbital Eccentricity (e) | 0.39900 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.3 g/cm³ (32.4 km/s vesc) |
| Insolation Flux | 191.9541 S⊕ (~261,250 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 293.100 LY (89.862 pc) |