HD 52265 b
Astrophysical Synthesis & Habitability Characterization
HD 52265 b is a confirmed gas giant exoplanet orbiting the star HD 52265, located approximately 97.8 light-years (29.98 parsecs) from the Solar System. First announced in 2000 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 13.7 Earth radii (1.22 Jupiter radii) and has a measured mass of 384.574 Earth masses (1.21 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.82 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2.05 g⊕ (20.1 m/s²), and an escape velocity of 59.3 km/s.
In its orbital architecture around HD 52265, HD 52265 b completes one full revolution every 119.27 Earth days at a semi-major axis of 0.52 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 47.4 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.27, swinging from 0.3796 AU at periapsis out to 0.6604 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 405 K (+132°C / +270°F) and receiving 7.33 S⊕ (~9,974 W/m²), HD 52265 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 52265 is classified as a solar-type yellow star of spectral type G0V with an effective photospheric temperature of 6,136 K, a radius of 1.32 R☉, a mass of 1.204 M☉, an estimated bolometric luminosity of 2.216 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.5 Gyr and a metallicity of [Fe/H] = 0.21 dex (metal-rich relative to the Sun). From Earth, HD 52265 shines at apparent V-band magnitude 6.294 (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 52265 |
| Spectral Type | G0V |
| Effective Temp (Teff) | 6,136 K |
| Stellar Radius | 1.3200 R☉ |
| Stellar Mass | 1.2040 M☉ |
| Bolometric Luminosity | 2.216 L☉ |
| Metallicity [Fe/H] | 0.210 dex |
| Stellar Age | 3.500 Gyr |
| Apparent Magnitude | V: 6.294 · G: 6.153 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.520000 AU |
| Orbital Period | 119.27 days |
| Mean Orbital Velocity | 47.4 km/s |
| Orbital Eccentricity (e) | 0.27000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.82 g/cm³ (59.3 km/s vesc) |
| Insolation Flux | 7.3281 S⊕ (~9,974 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 97.800 LY (29.980 pc) |