HD 136118 b
Astrophysical Synthesis & Habitability Characterization
HD 136118 b is a confirmed gas giant exoplanet orbiting the star HD 136118, located approximately 167.8 light-years (51.44 parsecs) from the Solar System. First announced in 2022 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.3 Earth radii (1.1 Jupiter radii) and has a measured mass of 4164.188 Earth masses (13.1 Jupiter masses). Combining its mass and radius yields a mean bulk density of 12.34 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 27.52 g⊕ (269.88 m/s²), and an escape velocity of 205.8 km/s.
In its orbital architecture around HD 136118, HD 136118 b completes one full revolution every 1187.598 Earth days (3.25Julian years) at a semi-major axis of 2.327 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 21.3 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.344, swinging from 1.5265 AU at periapsis out to 3.1275 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 12.300 R⊕, HD 136118 b 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 136118 is classified as a warm F-type star of spectral type F7 V with an effective photospheric temperature of 6,097 K, a radius of 1.6775 R☉, a mass of 1.18 M☉, an estimated bolometric luminosity of 3.489 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.05 dex (near-solar heavy-element abundance). From Earth, HD 136118 shines at apparent V-band magnitude 6.946 (accessible to binoculars and small amateur telescopes) in the Southern 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: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 136118 |
| Spectral Type | F7 V |
| Effective Temp (Teff) | 6,097 K |
| Stellar Radius | 1.6775 R☉ |
| Stellar Mass | 1.1800 M☉ |
| Bolometric Luminosity | 3.489 L☉ |
| Metallicity [Fe/H] | -0.050 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 6.946 · G: 6.797 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 2.327000 AU |
| Orbital Period | 1187.598 days |
| Mean Orbital Velocity | 21.3 km/s |
| Orbital Eccentricity (e) | 0.34400 |
| Orbital Inclination (i) | 116.7790° |
| Mean Bulk Density | 12.34 g/cm³ (205.8 km/s vesc) |
| Insolation Flux | 0.6840 S⊕ (~931 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 167.800 LY (51.436 pc) |