HD 34445 b
Astrophysical Synthesis & Habitability Characterization
HD 34445 b is a confirmed gas giant exoplanet orbiting the star HD 34445, located approximately 150.3 light-years (46.09 parsecs) from the Solar System. First announced in 2009 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 13.9 Earth radii (1.24 Jupiter radii) and has a measured mass of 260.621 Earth masses (0.82 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.54 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.35 g⊕ (13.24 m/s²), and an escape velocity of 48.4 km/s.
In its orbital architecture around HD 34445, HD 34445 b completes one full revolution every 1049 Earth days (2.87Julian years) at a semi-major axis of 2.07 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 21.5 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.27, swinging from 1.5111 AU at periapsis out to 2.6289 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 13.900 R⊕, HD 34445 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 34445 is classified as a solar-type yellow star of spectral type G0 V with an effective photospheric temperature of 5,879 K, a radius of 1.38 R☉, a mass of 1.14 M☉, an estimated bolometric luminosity of 2.041 L☉. Stellar evolution modeling indicates an estimated stellar age of 8.5 Gyr and a metallicity of [Fe/H] = 0.18 dex (metal-rich relative to the Sun). From Earth, HD 34445 shines at apparent V-band magnitude 7.31 (accessible to binoculars and small amateur telescopes) in the Northern celestial hemisphere. The HD 34445 system is a multi-planet architecture hosting 6 confirmed worlds, with HD 34445 b sharing its stellar neighborhood alongside HD 34445 e, HD 34445 d, HD 34445 c, HD 34445 f, HD 34445 g.
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 34445 |
| Spectral Type | G0 V |
| Effective Temp (Teff) | 5,879 K |
| Stellar Radius | 1.3800 R☉ |
| Stellar Mass | 1.1400 M☉ |
| Bolometric Luminosity | 2.041 L☉ |
| Metallicity [Fe/H] | 0.180 dex |
| Stellar Age | 8.500 Gyr |
| Apparent Magnitude | V: 7.310 · G: 7.149 |
| System Architecture | 1 Star, 6 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 2.070000 AU |
| Orbital Period | 1049 days |
| Mean Orbital Velocity | 21.5 km/s |
| Orbital Eccentricity (e) | 0.27000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.54 g/cm³ (48.4 km/s vesc) |
| Insolation Flux | 0.4691 S⊕ (~638 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 150.300 LY (46.091 pc) |