HD 154391 b
Astrophysical Synthesis & Habitability Characterization
HD 154391 b is a confirmed gas giant exoplanet orbiting the star HD 154391, located approximately 329.2 light-years (100.95 parsecs) from the Solar System. First announced in 2023 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.5 Earth radii (1.12 Jupiter radii) and has a measured mass of 2892.239 Earth masses (9.1 Jupiter masses). Combining its mass and radius yields a mean bulk density of 8.17 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 18.51 g⊕ (181.52 m/s²), and an escape velocity of 170.2 km/s.
In its orbital architecture around HD 154391, HD 154391 b completes one full revolution every 5163 Earth days (14.14Julian years) at a semi-major axis of 7.46 AU (a wide outer-system orbit beyond Jupiter's 5.20 AU distance in our Solar System). Its mean orbital velocity is approximately 15.7 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.2 carries the world between 5.968 AU at periapsis and 8.952 AU at apoapsis, driving measurable seasonal insolation cycles.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 12.500 R⊕, HD 154391 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 154391 is classified as an orange K-type star of spectral type K1 III with an effective photospheric temperature of 4,909 K, a radius of 8.56 R☉, a mass of 2.07 M☉, an estimated bolometric luminosity of 38.178 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.1 Gyr and a metallicity of [Fe/H] = 0.1 dex (metal-rich relative to the Sun). From Earth, HD 154391 shines at apparent V-band magnitude 6.155 (visible to the unaided human eye under dark skies) 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: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 154391 |
| Spectral Type | K1 III |
| Effective Temp (Teff) | 4,909 K |
| Stellar Radius | 8.5600 R☉ |
| Stellar Mass | 2.0700 M☉ |
| Bolometric Luminosity | 38.178 L☉ |
| Metallicity [Fe/H] | 0.100 dex |
| Stellar Age | 1.100 Gyr |
| Apparent Magnitude | V: 6.155 · G: 5.899 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 7.460000 AU |
| Orbital Period | 5163 days |
| Mean Orbital Velocity | 15.7 km/s |
| Orbital Eccentricity (e) | 0.20000 |
| Orbital Inclination (i) | 47.0000° |
| Mean Bulk Density | 8.17 g/cm³ (170.2 km/s vesc) |
| Insolation Flux | 0.6850 S⊕ (~932 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 329.200 LY (100.947 pc) |