BD+55 362 b
Astrophysical Synthesis & Habitability Characterization
BD+55 362 b is a confirmed gas giant exoplanet orbiting the star BD+55 362, located approximately 171.5 light-years (52.57 parsecs) from the Solar System. First announced in 2021 by Haute-Provence Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 14 Earth radii (1.25 Jupiter radii) and has a measured mass of 228.836 Earth masses (0.72 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.46 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.17 g⊕ (11.47 m/s²), and an escape velocity of 45.2 km/s.
In its orbital architecture around BD+55 362, BD+55 362 b completes one full revolution every 265.59 Earth days at a semi-major axis of 0.78 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 32 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.27, swinging from 0.5694 AU at periapsis out to 0.9906 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 14.000 R⊕, BD+55 362 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 BD+55 362 is classified as an orange K-type star of spectral type K3 with an effective photospheric temperature of 5,012 K, a radius of 0.8962 R☉, a mass of 0.909 M☉, an estimated bolometric luminosity of 0.455 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.18 dex (metal-rich relative to the Sun). From Earth, BD+55 362 shines at apparent V-band magnitude 9.38 (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: Haute-Provence Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | BD+55 362 |
| Spectral Type | K3 |
| Effective Temp (Teff) | 5,012 K |
| Stellar Radius | 0.8962 R☉ |
| Stellar Mass | 0.9090 M☉ |
| Bolometric Luminosity | 0.455 L☉ |
| Metallicity [Fe/H] | 0.180 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 9.380 · G: 9.153 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.780000 AU |
| Orbital Period | 265.59 days |
| Mean Orbital Velocity | 32 km/s |
| Orbital Eccentricity (e) | 0.27000 |
| Orbital Inclination (i) | 0.6012° |
| Mean Bulk Density | 0.46 g/cm³ (45.2 km/s vesc) |
| Insolation Flux | 0.7996 S⊕ (~1,088 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 171.500 LY (52.570 pc) |