HIP 77900 b
Astrophysical Synthesis & Habitability Characterization
HIP 77900 b is a confirmed gas giant exoplanet orbiting the star HIP 77900, located approximately 492 light-years (150.86 parsecs) from the Solar System. First announced in 2024 by European Space Agency (ESA) Gaia Satellite using the Imaging detection technique (resolved directly via high-contrast coronagraphic or interferometric imaging), this world measures 12.1 Earth radii (1.08 Jupiter radii) and has a measured mass of 6674.397 Earth masses (21 Jupiter masses). Combining its mass and radius yields a mean bulk density of 20.77 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 45.59 g⊕ (447.09 m/s²), and an escape velocity of 262.7 km/s.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 2507 K (+2234°C / +4053°F), HIP 77900 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HIP 77900 is classified as a stellar host with an effective photospheric temperature of 13,646 K. From Earth, HIP 77900 shines at apparent V-band magnitude 6.15 (visible to the unaided human eye under dark skies) 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: European Space Agency (ESA) Gaia Satellite · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HIP 77900 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 13,646 K |
| Stellar Radius | — |
| Stellar Mass | — |
| Metallicity [Fe/H] | — |
| Stellar Age | — |
| Apparent Magnitude | V: 6.150 · G: 6.119 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 3319.000000 AU |
| Orbital Period | — |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 20.77 g/cm³ (262.7 km/s vesc) |
| Insolation Flux | — |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 492.000 LY (150.862 pc) |