HD 73526 c
Astrophysical Synthesis & Habitability Characterization
HD 73526 c 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 2005 by Anglo-Australian Telescope using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.3 Earth radii (1.19 Jupiter radii) and has a measured mass of 715.09 Earth masses (2.25 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.68 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 4.04 g⊕ (39.62 m/s²), and an escape velocity of 82 km/s.
In its orbital architecture around HD 73526, HD 73526 c completes one full revolution every 379.1 Earth days (1.04Julian years) at a semi-major axis of 1.03 AU (comparable to the inner terrestrial zone between Venus, Earth at 1.00 AU, and Mars at 1.52 AU). Its mean orbital velocity is approximately 29.6 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.28, swinging from 0.7416 AU at periapsis out to 1.3184 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 13.300 R⊕, HD 73526 c 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 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 1.014 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 c sharing its stellar neighborhood alongside HD 73526 b.
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 | 1.0140 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) | 1.030000 AU |
| Orbital Period | 379.1 days |
| Mean Orbital Velocity | 29.6 km/s |
| Orbital Eccentricity (e) | 0.28000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.68 g/cm³ (82 km/s vesc) |
| Insolation Flux | 2.0521 S⊕ (~2,793 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 317.200 LY (97.240 pc) |