HIP 65426 b
Astrophysical Synthesis & Habitability Characterization
HIP 65426 b is a confirmed gas giant exoplanet orbiting the star HIP 65426, located approximately 355.1 light-years (108.88 parsecs) from the Solar System. First announced in 2017 by Paranal Observatory using the Imaging detection technique (resolved directly via high-contrast coronagraphic or interferometric imaging), this world measures 16.814 Earth radii (1.5 Jupiter radii) and has a measured mass of 2860.47 Earth masses (9 Jupiter masses). Combining its mass and radius yields a mean bulk density of 3.32 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 10.12 g⊕ (99.24 m/s²), and an escape velocity of 145.9 km/s.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1500 K (+1227°C / +2241°F) and receiving 0.00 S⊕ (~3 W/m²), HIP 65426 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HIP 65426 is classified as a luminous A-type star of spectral type A2 V with an effective photospheric temperature of 8,840 K, a radius of 1.77 R☉, a mass of 1.96 M☉, an estimated bolometric luminosity of 17.165 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.014 Gyr. From Earth, HIP 65426 shines at apparent V-band magnitude 7.01 (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: Paranal Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HIP 65426 |
| Spectral Type | A2 V |
| Effective Temp (Teff) | 8,840 K |
| Stellar Radius | 1.7700 R☉ |
| Stellar Mass | 1.9600 M☉ |
| Bolometric Luminosity | 17.165 L☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | 0.014 Gyr |
| Apparent Magnitude | V: 7.010 · G: 6.983 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 92.000000 AU |
| Orbital Period | — |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 3.32 g/cm³ (145.9 km/s vesc) |
| Insolation Flux | 0.0022 S⊕ (~3 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 355.100 LY (108.875 pc) |