HD 73526 b
Astrophysical Synthesis & Habitability Characterization
HD 73526 b is a confirmed gas giant exoplanet orbiting the star HD 73526, located approximately 317.2 light-years (97.24 parsecs) from the Solar System. First announced in 2002 by Anglo-Australian Telescope using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.1 Earth radii (1.17 Jupiter radii) and has a measured mass of 978.916 Earth masses (3.08 Jupiter masses). Combining its mass and radius yields a mean bulk density of 2.4 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 5.7 g⊕ (55.9 m/s²), and an escape velocity of 96.7 km/s.
In its orbital architecture around HD 73526, HD 73526 b completes one full revolution every 188.3 Earth days at a semi-major axis of 0.65 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 37.6 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.19 carries the world between 0.5265 AU at periapsis and 0.7735 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 414 K (+141°C / +286°F) and receiving 5.15 S⊕ (~7,013 W/m²), HD 73526 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 73526 is classified as a solar-type yellow star of spectral type G6 V with an effective photospheric temperature of 5,601 K, a radius of 1.53 R☉, a mass of 1.14 M☉, an estimated bolometric luminosity of 2.067 L☉. Stellar evolution modeling indicates an estimated stellar age of 9.2 Gyr and a metallicity of [Fe/H] = 0.22 dex (metal-rich relative to the Sun). From Earth, HD 73526 shines at apparent V-band magnitude 8.99 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The HD 73526 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 73526 b sharing its stellar neighborhood alongside HD 73526 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: Anglo-Australian Telescope · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 73526 |
| Spectral Type | G6 V |
| Effective Temp (Teff) | 5,601 K |
| Stellar Radius | 1.5300 R☉ |
| Stellar Mass | 1.1400 M☉ |
| Bolometric Luminosity | 2.067 L☉ |
| Metallicity [Fe/H] | 0.220 dex |
| Stellar Age | 9.200 Gyr |
| Apparent Magnitude | V: 8.990 · G: 8.797 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.650000 AU |
| Orbital Period | 188.3 days |
| Mean Orbital Velocity | 37.6 km/s |
| Orbital Eccentricity (e) | 0.19000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 2.4 g/cm³ (96.7 km/s vesc) |
| Insolation Flux | 5.1529 S⊕ (~7,013 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 317.200 LY (97.240 pc) |