HD 45364 c
Astrophysical Synthesis & Habitability Characterization
HD 45364 c 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 14.2 Earth radii (1.27 Jupiter radii) and has a measured mass of 174.488 Earth masses (0.55 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.34 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.87 g⊕ (8.53 m/s²), and an escape velocity of 39.2 km/s.
In its orbital architecture around HD 45364, HD 45364 c completes one full revolution every 345.43 Earth days at a semi-major axis of 0.902 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 28.4 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.019 (ranging from 0.8849 AU at periapsis to 0.9191 AU at apoapsis), the planet experiences minimal orbital distance variation.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 14.200 R⊕, HD 45364 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 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 c sharing its stellar neighborhood alongside HD 45364 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: 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) | 0.902000 AU |
| Orbital Period | 345.43 days |
| Mean Orbital Velocity | 28.4 km/s |
| Orbital Eccentricity (e) | 0.01900 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.34 g/cm³ (39.2 km/s vesc) |
| Insolation Flux | 0.7829 S⊕ (~1,066 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 112.000 LY (34.354 pc) |