HD 154345 b
Astrophysical Synthesis & Habitability Characterization
HD 154345 b is a confirmed gas giant exoplanet orbiting the star HD 154345, located approximately 59.6 light-years (18.28 parsecs) from the Solar System. First announced in 2006 by W. M. Keck Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.7 Earth radii (1.22 Jupiter radii) and has a measured mass of 376.944 Earth masses (1.19 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.81 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2.01 g⊕ (19.71 m/s²), and an escape velocity of 58.7 km/s.
In its orbital architecture around HD 154345, HD 154345 b completes one full revolution every 3280 Earth days (8.98Julian years) at a semi-major axis of 4.158 AU (corresponding to the middle-system regime between Mars at 1.52 AU and Jupiter at 5.20 AU). Its mean orbital velocity is approximately 13.8 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.058 carries the world between 3.9168 AU at periapsis and 4.3992 AU at apoapsis, driving measurable seasonal insolation cycles.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 119 K (-154°C / -245°F) and an incident flux of 0.03 S⊕ (~47 W/m²), surface water and volatile species on HD 154345 b would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star HD 154345 is classified as a solar-type yellow star of spectral type G8 with an effective photospheric temperature of 5,468 K, a radius of 0.85 R☉, a mass of 0.89 M☉, an estimated bolometric luminosity of 0.579 L☉. Stellar evolution modeling indicates an estimated stellar age of 9.527 Gyr and a metallicity of [Fe/H] = -0.105 dex (metal-poor relative to the Sun). From Earth, HD 154345 shines at apparent V-band magnitude 6.76 (accessible to binoculars and small amateur telescopes) in the Northern 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: W. M. Keck Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 154345 |
| Spectral Type | G8 |
| Effective Temp (Teff) | 5,468 K |
| Stellar Radius | 0.8500 R☉ |
| Stellar Mass | 0.8900 M☉ |
| Bolometric Luminosity | 0.579 L☉ |
| Metallicity [Fe/H] | -0.105 dex |
| Stellar Age | 9.527 Gyr |
| Apparent Magnitude | V: 6.760 · G: 6.568 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 4.158000 AU |
| Orbital Period | 3280 days |
| Mean Orbital Velocity | 13.8 km/s |
| Orbital Eccentricity (e) | 0.05800 |
| Orbital Inclination (i) | 88.0000° |
| Mean Bulk Density | 0.81 g/cm³ (58.7 km/s vesc) |
| Insolation Flux | 0.0349 S⊕ (~47 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 59.600 LY (18.284 pc) |