HD 34445 e
Astrophysical Synthesis & Habitability Characterization
HD 34445 e is a confirmed sub-neptune exoplanet orbiting the star HD 34445, located approximately 150.3 light-years (46.09 parsecs) from the Solar System. First announced in 2017 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 4.26 Earth radii (0.38 Jupiter radii) and has a measured mass of 16.8 Earth masses. Combining its mass and radius yields a mean bulk density of 1.2 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.93 g⊕ (9.12 m/s²), and an escape velocity of 22.2 km/s.
In its orbital architecture around HD 34445, HD 34445 e completes one full revolution every 49.175 Earth days at a semi-major axis of 0.2687 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 59.4 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.09 carries the world between 0.2445 AU at periapsis and 0.2929 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 638 K (+365°C / +689°F) and receiving 27.84 S⊕ (~37,890 W/m²), HD 34445 e orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 34445 is classified as a solar-type yellow star of spectral type G0 V with an effective photospheric temperature of 5,836 K, a radius of 1.38 R☉, a mass of 1.07 M☉, an estimated bolometric luminosity of 1.982 L☉. Stellar evolution modeling indicates an estimated stellar age of 8.5 Gyr and a metallicity of [Fe/H] = 0.14 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 e sharing its stellar neighborhood alongside HD 34445 d, HD 34445 c, HD 34445 f, HD 34445 b, 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: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 34445 |
| Spectral Type | G0 V |
| Effective Temp (Teff) | 5,836 K |
| Stellar Radius | 1.3800 R☉ |
| Stellar Mass | 1.0700 M☉ |
| Bolometric Luminosity | 1.982 L☉ |
| Metallicity [Fe/H] | 0.140 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) | 0.268700 AU |
| Orbital Period | 49.175 days |
| Mean Orbital Velocity | 59.4 km/s |
| Orbital Eccentricity (e) | 0.09000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.2 g/cm³ (22.2 km/s vesc) |
| Insolation Flux | 27.8395 S⊕ (~37,890 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 150.300 LY (46.091 pc) |