HD 48265 b
Astrophysical Synthesis & Habitability Characterization
HD 48265 b is a confirmed gas giant exoplanet orbiting the star HD 48265, located approximately 295.3 light-years (90.55 parsecs) from the Solar System. First announced in 2008 by Las Campanas Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.6 Earth radii (1.12 Jupiter radii) and has a measured mass of 2351.93 Earth masses (7.4 Jupiter masses). Combining its mass and radius yields a mean bulk density of 6.48 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 14.81 g⊕ (145.24 m/s²), and an escape velocity of 152.8 km/s.
In its orbital architecture around HD 48265, HD 48265 b completes one full revolution every 778.51 Earth days (2.13Julian years) at a semi-major axis of 1.814 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 25.3 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.211 carries the world between 1.4312 AU at periapsis and 2.1968 AU at apoapsis, driving measurable seasonal insolation cycles.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 12.600 R⊕, HD 48265 b exceeds the empirical ~1.8–2.2 R⊕ Fulton radius valley threshold, indicating a substantial hydrogen-helium or supercritical volatile envelope without a conventional solid terrestrial surface.
The host star HD 48265 is classified as a solar-type yellow star of spectral type G5 IV/V with an effective photospheric temperature of 5,733 K, a radius of 1.901 R☉, a mass of 1.312 M☉, an estimated bolometric luminosity of 3.503 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.201 Gyr and a metallicity of [Fe/H] = 0.3 dex (metal-rich relative to the Sun). From Earth, HD 48265 shines at apparent V-band magnitude 8.05 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The HD 48265 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 48265 b sharing its stellar neighborhood alongside HD 48265 c.
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: Las Campanas Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 48265 |
| Spectral Type | G5 IV/V |
| Effective Temp (Teff) | 5,733 K |
| Stellar Radius | 1.9010 R☉ |
| Stellar Mass | 1.3120 M☉ |
| Bolometric Luminosity | 3.503 L☉ |
| Metallicity [Fe/H] | 0.300 dex |
| Stellar Age | 4.201 Gyr |
| Apparent Magnitude | V: 8.050 · G: 7.879 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.814000 AU |
| Orbital Period | 778.51 days |
| Mean Orbital Velocity | 25.3 km/s |
| Orbital Eccentricity (e) | 0.21100 |
| Orbital Inclination (i) | 11.7000° |
| Mean Bulk Density | 6.48 g/cm³ (152.8 km/s vesc) |
| Insolation Flux | 1.1670 S⊕ (~1,588 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 295.300 LY (90.545 pc) |