HD 37605 b
Astrophysical Synthesis & Habitability Characterization
HD 37605 b is a confirmed gas giant exoplanet orbiting the star HD 37605, located approximately 152.6 light-years (46.79 parsecs) from the Solar System. First announced in 2004 by McDonald Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.2 Earth radii (1.18 Jupiter radii) and has a measured mass of 854.963 Earth masses (2.69 Jupiter masses). Combining its mass and radius yields a mean bulk density of 2.05 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 4.91 g⊕ (48.15 m/s²), and an escape velocity of 90 km/s.
In its orbital architecture around HD 37605, HD 37605 b completes one full revolution every 55.013 Earth days at a semi-major axis of 0.277 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 54.8 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.6745, swinging from 0.0902 AU at periapsis out to 0.4638 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 466 K (+193°C / +379°F) and receiving 7.85 S⊕ (~10,688 W/m²), HD 37605 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 37605 is classified as an orange K-type star of spectral type K0 with an effective photospheric temperature of 5,329 K, a radius of 0.91 R☉, a mass of 0.94 M☉, an estimated bolometric luminosity of 0.599 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.65 Gyr and a metallicity of [Fe/H] = 0.27 dex (metal-rich relative to the Sun). From Earth, HD 37605 shines at apparent V-band magnitude 8.67 (accessible to binoculars and small amateur telescopes) in the Northern celestial hemisphere. The HD 37605 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 37605 b sharing its stellar neighborhood alongside HD 37605 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: McDonald Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 37605 |
| Spectral Type | K0 |
| Effective Temp (Teff) | 5,329 K |
| Stellar Radius | 0.9100 R☉ |
| Stellar Mass | 0.9400 M☉ |
| Bolometric Luminosity | 0.599 L☉ |
| Metallicity [Fe/H] | 0.270 dex |
| Stellar Age | 5.650 Gyr |
| Apparent Magnitude | V: 8.670 · G: 8.462 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.277000 AU |
| Orbital Period | 55.013 days |
| Mean Orbital Velocity | 54.8 km/s |
| Orbital Eccentricity (e) | 0.67450 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 2.05 g/cm³ (90 km/s vesc) |
| Insolation Flux | 7.8531 S⊕ (~10,688 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 152.600 LY (46.786 pc) |