HD 56957 b

Astrophysical Synthesis & Habitability Characterization

HD 56957 b is a confirmed gas giant exoplanet orbiting the star HD 56957, located approximately 200.6 light-years (61.49 parsecs) from the Solar System. First announced in 2022 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.8 Earth radii (1.14 Jupiter radii) and has a measured mass of 1880.909 Earth masses (5.92 Jupiter masses). Combining its mass and radius yields a mean bulk density of 4.95 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 11.48 g⊕ (112.58 m/s²), and an escape velocity of 135.6 km/s.

In its orbital architecture around HD 56957, HD 56957 b completes one full revolution every 5859.09 Earth days (16.04Julian years) at a semi-major axis of 6.426 AU (a wide outer-system orbit beyond Jupiter's 5.20 AU distance in our Solar System). Its mean orbital velocity is approximately 11.9 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.273, swinging from 4.6717 AU at periapsis out to 8.1803 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.

❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 146 K (-127°C / -197°F) and an incident flux of 0.08 S⊕ (~102 W/m²), surface water and volatile species on HD 56957 b would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.

The host star HD 56957 is classified as a stellar host with an effective photospheric temperature of 5,743 K, a radius of 1.7779 R☉, a mass of 1.03 M☉, an estimated bolometric luminosity of 3.085 L☉. From Earth, HD 56957 shines at apparent V-band magnitude 7.57 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere.

Discovery Facility: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).