HD 115954 b
Astrophysical Synthesis & Habitability Characterization
HD 115954 b is a confirmed gas giant exoplanet orbiting the star HD 115954, located approximately 285.9 light-years (87.64 parsecs) from the Solar System. First announced in 2021 by Haute-Provence Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.6 Earth radii (1.12 Jupiter radii) and has a measured mass of 2685.65 Earth masses (8.45 Jupiter masses). Combining its mass and radius yields a mean bulk density of 7.4 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 16.92 g⊕ (165.93 m/s²), and an escape velocity of 163.3 km/s.
In its orbital architecture around HD 115954, HD 115954 b completes one full revolution every 3700 Earth days (10.13Julian years) at a semi-major axis of 5 AU (corresponding to the middle-system regime between Mars at 1.52 AU and Jupiter at 5.20 AU). Its mean orbital velocity is approximately 14.7 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.487, swinging from 2.565 AU at periapsis out to 7.435 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 145 K (-128°C / -198°F) and an incident flux of 0.06 S⊕ (~87 W/m²), surface water and volatile species on HD 115954 b would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star HD 115954 is classified as a solar-type yellow star of spectral type G0 V with an effective photospheric temperature of 5,957 K, a radius of 1.213 R☉, a mass of 1.18 M☉, an estimated bolometric luminosity of 1.662 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.34 dex (metal-rich relative to the Sun). From Earth, HD 115954 shines at apparent V-band magnitude 8.34 (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: Haute-Provence Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 115954 |
| Spectral Type | G0 V |
| Effective Temp (Teff) | 5,957 K |
| Stellar Radius | 1.2130 R☉ |
| Stellar Mass | 1.1800 M☉ |
| Bolometric Luminosity | 1.662 L☉ |
| Metallicity [Fe/H] | 0.340 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 8.340 · G: 8.187 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 5.000000 AU |
| Orbital Period | 3700 days |
| Mean Orbital Velocity | 14.7 km/s |
| Orbital Eccentricity (e) | 0.48700 |
| Orbital Inclination (i) | 79.0000° |
| Mean Bulk Density | 7.4 g/cm³ (163.3 km/s vesc) |
| Insolation Flux | 0.0640 S⊕ (~87 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 285.900 LY (87.644 pc) |