HIP 97166 c
Astrophysical Synthesis & Habitability Characterization
HIP 97166 c is a confirmed sub-neptune exoplanet orbiting the star HIP 97166, located approximately 215.1 light-years (65.95 parsecs) from the Solar System. First announced in 2021 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 2.75 Earth radii and has a measured mass of 8 Earth masses. Combining its mass and radius yields a mean bulk density of 2.12 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.06 g⊕ (10.4 m/s²), and an escape velocity of 19.1 km/s.
In its orbital architecture around HIP 97166, HIP 97166 c completes one full revolution every 16.432 Earth days at a semi-major axis of 0.124 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 82.1 km/s (compared to Earth's 29.8 km/s). The orbit is modeled as circular (e = 0.00), maintaining a constant stellar distance throughout its year.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 642 K (+369°C / +696°F) and receiving 30.76 S⊕ (~41,867 W/m²), HIP 97166 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HIP 97166 is classified as an orange K-type star of spectral type K0 V with an effective photospheric temperature of 5,216 K, a radius of 0.8418 R☉, a mass of 0.9342 M☉, an estimated bolometric luminosity of 0.471 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.2 Gyr and a metallicity of [Fe/H] = 0.248 dex (metal-rich relative to the Sun). From Earth, HIP 97166 shines at apparent V-band magnitude 9.92 (accessible to binoculars and small amateur telescopes) in the Northern celestial hemisphere. The HIP 97166 system is a multi-planet architecture hosting 2 confirmed worlds, with HIP 97166 c sharing its stellar neighborhood alongside HIP 97166 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 Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HIP 97166 |
| Spectral Type | K0 V |
| Effective Temp (Teff) | 5,216 K |
| Stellar Radius | 0.8418 R☉ |
| Stellar Mass | 0.9342 M☉ |
| Bolometric Luminosity | 0.471 L☉ |
| Metallicity [Fe/H] | 0.248 dex |
| Stellar Age | 1.200 Gyr |
| Apparent Magnitude | V: 9.920 · G: 9.684 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.124000 AU |
| Orbital Period | 16.432 days |
| Mean Orbital Velocity | 82.1 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 2.12 g/cm³ (19.1 km/s vesc) |
| Insolation Flux | 30.7622 S⊕ (~41,867 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 215.100 LY (65.950 pc) |