HIP 54515 b
Astrophysical Synthesis & Habitability Characterization
HIP 54515 b is a confirmed gas giant exoplanet orbiting the star HIP 54515, located approximately 270.1 light-years (82.81 parsecs) from the Solar System. First announced in 2026 by Subaru Telescope using the Imaging detection technique (resolved directly via high-contrast coronagraphic or interferometric imaging), this world measures 12.2 Earth radii (1.09 Jupiter radii) and has a measured mass of 5625.563 Earth masses (17.7 Jupiter masses). Combining its mass and radius yields a mean bulk density of 17.08 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 37.8 g⊕ (370.69 m/s²), and an escape velocity of 240.2 km/s.
In its orbital architecture around HIP 54515, HIP 54515 b completes one full revolution every 33000 Earth days (90.35Julian years) at a semi-major axis of 24.8 AU (a wide outer-system orbit beyond Jupiter's 5.20 AU distance in our Solar System). Its mean orbital velocity is approximately 8.2 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.42, swinging from 14.384 AU at periapsis out to 35.216 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 101 K (-172°C / -278°F) and an incident flux of 0.02 S⊕ (~23 W/m²), surface water and volatile species on HIP 54515 b would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star HIP 54515 is classified as a luminous A-type star of spectral type A5 V with an effective photospheric temperature of 8,100 K, a radius of 1.6492 R☉, a mass of 1.9 M☉, an estimated bolometric luminosity of 10.505 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.115 Gyr. From Earth, HIP 54515 shines at apparent V-band magnitude 6.807 (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: Subaru Telescope · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HIP 54515 |
| Spectral Type | A5 V |
| Effective Temp (Teff) | 8,100 K |
| Stellar Radius | 1.6492 R☉ |
| Stellar Mass | 1.9000 M☉ |
| Bolometric Luminosity | 10.505 L☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | 0.115 Gyr |
| Apparent Magnitude | V: 6.807 · G: 6.769 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 24.800000 AU |
| Orbital Period | 33000 days |
| Mean Orbital Velocity | 8.2 km/s |
| Orbital Eccentricity (e) | 0.42000 |
| Orbital Inclination (i) | 129.6000° |
| Mean Bulk Density | 17.08 g/cm³ (240.2 km/s vesc) |
| Insolation Flux | 0.0171 S⊕ (~23 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 270.100 LY (82.810 pc) |