HIP 21152 b
Astrophysical Synthesis & Habitability Characterization
HIP 21152 b is a confirmed gas giant exoplanet orbiting the star HIP 21152, located approximately 141.6 light-years (43.41 parsecs) from the Solar System. First announced in 2022 by Multiple Observatories using the Imaging detection technique (resolved directly via high-contrast coronagraphic or interferometric imaging), this world measures 12 Earth radii (1.07 Jupiter radii) and has a measured mass of 7627.882 Earth masses (24 Jupiter masses). Combining its mass and radius yields a mean bulk density of 24.34 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 52.97 g⊕ (519.46 m/s²), and an escape velocity of 282 km/s.
In its orbital architecture around HIP 21152, HIP 21152 b completes one full revolution every 22000 Earth days (60.23Julian years) at a semi-major axis of 17 AU (a wide outer-system orbit beyond Jupiter's 5.20 AU distance in our Solar System). Its mean orbital velocity is approximately 8.4 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.36, swinging from 10.88 AU at periapsis out to 23.12 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1300 K (+1027°C / +1881°F) and receiving 0.02 S⊕ (~20 W/m²), HIP 21152 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HIP 21152 is classified as a warm F-type star of spectral type F5 V with an effective photospheric temperature of 6,655 K, a radius of 1.5919 R☉, a mass of 1.4 M☉, an estimated bolometric luminosity of 4.46 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.65 Gyr and a metallicity of [Fe/H] = 0.13 dex (metal-rich relative to the Sun). From Earth, HIP 21152 shines at apparent V-band magnitude 6.37 (accessible to binoculars and small amateur telescopes) in the Northern 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: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HIP 21152 |
| Spectral Type | F5 V |
| Effective Temp (Teff) | 6,655 K |
| Stellar Radius | 1.5919 R☉ |
| Stellar Mass | 1.4000 M☉ |
| Bolometric Luminosity | 4.46 L☉ |
| Metallicity [Fe/H] | 0.130 dex |
| Stellar Age | 0.650 Gyr |
| Apparent Magnitude | V: 6.370 · G: 6.256 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 17.000000 AU |
| Orbital Period | 22000 days |
| Mean Orbital Velocity | 8.4 km/s |
| Orbital Eccentricity (e) | 0.36000 |
| Orbital Inclination (i) | 95.3000° |
| Mean Bulk Density | 24.34 g/cm³ (282 km/s vesc) |
| Insolation Flux | 0.0150 S⊕ (~20 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 141.600 LY (43.407 pc) |