HD 215497 c
Astrophysical Synthesis & Habitability Characterization
HD 215497 c is a confirmed gas giant exoplanet orbiting the star HD 215497, located approximately 132.2 light-years (40.55 parsecs) from the Solar System. First announced in 2009 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13 Earth radii (1.16 Jupiter radii) and has a measured mass of 111.24 Earth masses (0.35 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.28 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.66 g⊕ (6.47 m/s²), and an escape velocity of 32.7 km/s.
In its orbital architecture around HD 215497, HD 215497 c completes one full revolution every 566 Earth days (1.55Julian years) at a semi-major axis of 1.31 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 25.2 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.47, swinging from 0.6943 AU at periapsis out to 1.9257 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 13.000 R⊕, HD 215497 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 HD 215497 is classified as an orange K-type star of spectral type K3 V with an effective photospheric temperature of 5,113 K, a radius of 0.85 R☉, a mass of 0.92 M☉, an estimated bolometric luminosity of 0.443 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.8 Gyr and a metallicity of [Fe/H] = 0.23 dex (metal-rich relative to the Sun). From Earth, HD 215497 shines at apparent V-band magnitude 8.96 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The HD 215497 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 215497 c sharing its stellar neighborhood alongside HD 215497 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 | HD 215497 |
| Spectral Type | K3 V |
| Effective Temp (Teff) | 5,113 K |
| Stellar Radius | 0.8500 R☉ |
| Stellar Mass | 0.9200 M☉ |
| Bolometric Luminosity | 0.443 L☉ |
| Metallicity [Fe/H] | 0.230 dex |
| Stellar Age | 5.800 Gyr |
| Apparent Magnitude | V: 8.960 · G: 8.686 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.310000 AU |
| Orbital Period | 566 days |
| Mean Orbital Velocity | 25.2 km/s |
| Orbital Eccentricity (e) | 0.47000 |
| Orbital Inclination (i) | 90.0000° |
| Mean Bulk Density | 0.28 g/cm³ (32.7 km/s vesc) |
| Insolation Flux | 0.2267 S⊕ (~309 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 132.200 LY (40.547 pc) |