HIP 5158 c
Astrophysical Synthesis & Habitability Characterization
HIP 5158 c is a confirmed gas giant exoplanet orbiting the star HIP 5158, located approximately 168.3 light-years (51.6 parsecs) from the Solar System. First announced in 2011 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.2 Earth radii (1.09 Jupiter radii) and has a measured mass of 4780.163 Earth masses (15.04 Jupiter masses). Combining its mass and radius yields a mean bulk density of 14.52 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 32.12 g⊕ (314.99 m/s²), and an escape velocity of 221.4 km/s.
In its orbital architecture around HIP 5158, HIP 5158 c completes one full revolution every 9017.76 Earth days (24.69Julian years) at a semi-major axis of 7.7 AU (a wide outer-system orbit beyond Jupiter's 5.20 AU distance in our Solar System). Its mean orbital velocity is approximately 9.3 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.14 carries the world between 6.622 AU at periapsis and 8.778 AU at apoapsis, driving measurable seasonal insolation cycles.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 73 K (-200°C / -328°F) and an incident flux of 0.00 S⊕ (~6 W/m²), surface water and volatile species on HIP 5158 c would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star HIP 5158 is classified as a stellar host with an effective photospheric temperature of 4,813 K, a radius of 0.7541 R☉, a mass of 0.78 M☉, an estimated bolometric luminosity of 0.274 L☉. Stellar evolution modeling indicates an estimated stellar age of 6 Gyr and a metallicity of [Fe/H] = 0.17 dex (metal-rich relative to the Sun). From Earth, HIP 5158 shines at apparent V-band magnitude 10.16 (faint and requiring research-grade or CCD telescopic photometry) in the Southern celestial hemisphere. The HIP 5158 system is a multi-planet architecture hosting 2 confirmed worlds, with HIP 5158 c sharing its stellar neighborhood alongside HIP 5158 b.
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: La Silla Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HIP 5158 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,813 K |
| Stellar Radius | 0.7541 R☉ |
| Stellar Mass | 0.7800 M☉ |
| Bolometric Luminosity | 0.274 L☉ |
| Metallicity [Fe/H] | 0.170 dex |
| Stellar Age | 6.000 Gyr |
| Apparent Magnitude | V: 10.160 · G: 9.802 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 7.700000 AU |
| Orbital Period | 9017.76 days |
| Mean Orbital Velocity | 9.3 km/s |
| Orbital Eccentricity (e) | 0.14000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 14.52 g/cm³ (221.4 km/s vesc) |
| Insolation Flux | 0.0046 S⊕ (~6 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 168.300 LY (51.603 pc) |