HD 45364 b
Astrophysical Synthesis & Habitability Characterization
HD 45364 b is a confirmed gas giant exoplanet orbiting the star HD 45364, located approximately 112 light-years (34.35 parsecs) from the Solar System. First announced in 2008 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 9.03 Earth radii (0.81 Jupiter radii) and has a measured mass of 60.165 Earth masses (0.19 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.45 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.74 g⊕ (7.26 m/s²), and an escape velocity of 28.9 km/s.
In its orbital architecture around HD 45364, HD 45364 b completes one full revolution every 225.79 Earth days at a semi-major axis of 0.6793 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 32.7 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.067 carries the world between 0.6338 AU at periapsis and 0.7248 AU at apoapsis, driving measurable seasonal insolation cycles.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 9.030 R⊕, HD 45364 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 45364 is classified as an orange K-type star of spectral type K0 V with an effective photospheric temperature of 5,466 K, a radius of 0.89 R☉, a mass of 0.82 M☉, an estimated bolometric luminosity of 0.634 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.17 dex (metal-poor relative to the Sun). From Earth, HD 45364 shines at apparent V-band magnitude 8.08 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The HD 45364 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 45364 b sharing its stellar neighborhood alongside HD 45364 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: La Silla Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 45364 |
| Spectral Type | K0 V |
| Effective Temp (Teff) | 5,466 K |
| Stellar Radius | 0.8900 R☉ |
| Stellar Mass | 0.8200 M☉ |
| Bolometric Luminosity | 0.634 L☉ |
| Metallicity [Fe/H] | -0.170 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 8.080 · G: 7.880 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.679300 AU |
| Orbital Period | 225.79 days |
| Mean Orbital Velocity | 32.7 km/s |
| Orbital Eccentricity (e) | 0.06700 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.45 g/cm³ (28.9 km/s vesc) |
| Insolation Flux | 1.3804 S⊕ (~1,879 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 112.000 LY (34.354 pc) |