HD 68475 b
Astrophysical Synthesis & Habitability Characterization
HD 68475 b is a confirmed gas giant exoplanet orbiting the star HD 68475, located approximately 109 light-years (33.43 parsecs) from the Solar System. First announced in 2026 by Las Campanas Observatory 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 1639.995 Earth masses (5.16 Jupiter masses). Combining its mass and radius yields a mean bulk density of 4.31 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 10.01 g⊕ (98.16 m/s²), and an escape velocity of 126.6 km/s.
In its orbital architecture around HD 68475, HD 68475 b completes one full revolution every 7832 Earth days (21.44Julian years) at a semi-major axis of 7.27 AU (a wide outer-system orbit beyond Jupiter's 5.20 AU distance in our Solar System). Its mean orbital velocity is approximately 10.1 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.62, swinging from 2.7626 AU at periapsis out to 11.7774 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 80 K (-193°C / -315°F) and an incident flux of 0.01 S⊕ (~9 W/m²), surface water and volatile species on HD 68475 b would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star HD 68475 is classified as an orange K-type star of spectral type K2 VC with an effective photospheric temperature of 5,022 K, a radius of 0.791 R☉, a mass of 0.83 M☉, an estimated bolometric luminosity of 0.357 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.07 dex (metal-rich relative to the Sun). From Earth, HD 68475 shines at apparent V-band magnitude 8.78 (accessible to binoculars and small amateur telescopes) in the Southern 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: Las Campanas Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 68475 |
| Spectral Type | K2 VC |
| Effective Temp (Teff) | 5,022 K |
| Stellar Radius | 0.7910 R☉ |
| Stellar Mass | 0.8300 M☉ |
| Bolometric Luminosity | 0.357 L☉ |
| Metallicity [Fe/H] | 0.070 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 8.780 · G: 8.517 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 7.270000 AU |
| Orbital Period | 7832 days |
| Mean Orbital Velocity | 10.1 km/s |
| Orbital Eccentricity (e) | 0.62000 |
| Orbital Inclination (i) | 87.0000° |
| Mean Bulk Density | 4.31 g/cm³ (126.6 km/s vesc) |
| Insolation Flux | 0.0068 S⊕ (~9 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 109.000 LY (33.430 pc) |