HIP 10090 c
Astrophysical Synthesis & Habitability Characterization
HIP 10090 c is a confirmed gas giant exoplanet orbiting the star HIP 10090, located approximately 268.7 light-years (82.39 parsecs) from the Solar System. First announced in 2026 by Multiple Facilities using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.9 Earth radii (1.24 Jupiter radii) and has a measured mass of 270.154 Earth masses (0.85 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.55 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.4 g⊕ (13.73 m/s²), and an escape velocity of 49.3 km/s.
In its orbital architecture around HIP 10090, HIP 10090 c completes one full revolution every 321.82 Earth days at a semi-major axis of 0.9 AU (comparable to the inner terrestrial zone between Venus, Earth at 1.00 AU, and Mars at 1.52 AU). Its mean orbital velocity is approximately 30.4 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.188 carries the world between 0.7308 AU at periapsis and 1.0692 AU at apoapsis, driving measurable seasonal insolation cycles.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 13.900 R⊕, HIP 10090 c exceeds the empirical ~1.8–2.2 R⊕ Fulton radius valley threshold, indicating a substantial hydrogen-helium or supercritical volatile envelope without a conventional solid terrestrial surface.
The host star HIP 10090 is classified as an orange K-type star of spectral type K0 with an effective photospheric temperature of 5,661 K, a radius of 1.3827 R☉, a mass of 0.94 M☉, an estimated bolometric luminosity of 1.762 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.97 Gyr and a metallicity of [Fe/H] = 0.47 dex (metal-rich relative to the Sun). From Earth, HIP 10090 shines at apparent V-band magnitude 8.94 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The HIP 10090 system is a multi-planet architecture hosting 2 confirmed worlds, with HIP 10090 c sharing its stellar neighborhood alongside HIP 10090 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: Multiple Facilities · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HIP 10090 |
| Spectral Type | K0 |
| Effective Temp (Teff) | 5,661 K |
| Stellar Radius | 1.3827 R☉ |
| Stellar Mass | 0.9400 M☉ |
| Bolometric Luminosity | 1.762 L☉ |
| Metallicity [Fe/H] | 0.470 dex |
| Stellar Age | 4.970 Gyr |
| Apparent Magnitude | V: 8.940 · G: 8.764 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.900000 AU |
| Orbital Period | 321.82 days |
| Mean Orbital Velocity | 30.4 km/s |
| Orbital Eccentricity (e) | 0.18800 |
| Orbital Inclination (i) | 153.8000° |
| Mean Bulk Density | 0.55 g/cm³ (49.3 km/s vesc) |
| Insolation Flux | 1.9857 S⊕ (~2,703 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 268.700 LY (82.394 pc) |