HR 810 b
Astrophysical Synthesis & Habitability Characterization
HR 810 b is a confirmed gas giant exoplanet orbiting the star HR 810, located approximately 56.5 light-years (17.32 parsecs) from the Solar System. First announced in 1999 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.7 Earth radii (1.13 Jupiter radii) and has a measured mass of 1970.536 Earth masses (6.2 Jupiter masses). Combining its mass and radius yields a mean bulk density of 5.3 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 12.22 g⊕ (119.84 m/s²), and an escape velocity of 139.3 km/s.
In its orbital architecture around HR 810, HR 810 b completes one full revolution every 302.8 Earth days at a semi-major axis of 0.92 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 33.1 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.14 carries the world between 0.7912 AU at periapsis and 1.0488 AU at apoapsis, driving measurable seasonal insolation cycles.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 12.700 R⊕, HR 810 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 HR 810 is classified as a solar-type yellow star of spectral type G0V with an effective photospheric temperature of 6,167 K, a radius of 1.13 R☉, a mass of 1.34 M☉, an estimated bolometric luminosity of 1.657 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.72 Gyr and a metallicity of [Fe/H] = 0.16 dex (metal-rich relative to the Sun). From Earth, HR 810 shines at apparent V-band magnitude 5.4 (visible to the unaided human eye under dark skies) 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: La Silla Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HR 810 |
| Spectral Type | G0V |
| Effective Temp (Teff) | 6,167 K |
| Stellar Radius | 1.1300 R☉ |
| Stellar Mass | 1.3400 M☉ |
| Bolometric Luminosity | 1.657 L☉ |
| Metallicity [Fe/H] | 0.160 dex |
| Stellar Age | 2.720 Gyr |
| Apparent Magnitude | V: 5.400 · G: 5.256 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.920000 AU |
| Orbital Period | 302.8 days |
| Mean Orbital Velocity | 33.1 km/s |
| Orbital Eccentricity (e) | 0.14000 |
| Orbital Inclination (i) | 87.0000° |
| Mean Bulk Density | 5.3 g/cm³ (139.3 km/s vesc) |
| Insolation Flux | 2.1160 S⊕ (~2,880 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 56.500 LY (17.318 pc) |