HD 154088 b
Astrophysical Synthesis & Habitability Characterization
HD 154088 b is a confirmed sub-neptune exoplanet orbiting the star HD 154088, located approximately 59.6 light-years (18.27 parsecs) from the Solar System. First announced in 2021 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 2.46 Earth radii and has a measured mass of 6.6 Earth masses. Combining its mass and radius yields a mean bulk density of 2.44 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.09 g⊕ (10.69 m/s²), and an escape velocity of 18.3 km/s.
In its orbital architecture around HD 154088, HD 154088 b completes one full revolution every 18.56 Earth days at a semi-major axis of 0.134 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 78.5 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.344, swinging from 0.0879 AU at periapsis out to 0.1801 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 690 K (+417°C / +783°F) and receiving 41.21 S⊕ (~56,089 W/m²), HD 154088 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 154088 is classified as an orange K-type star of spectral type K0 IV-V with an effective photospheric temperature of 5,374 K, a radius of 0.95 R☉, a mass of 0.91 M☉, an estimated bolometric luminosity of 0.675 L☉. Stellar evolution modeling indicates an estimated stellar age of 8 Gyr and a metallicity of [Fe/H] = 0.28 dex (metal-rich relative to the Sun). From Earth, HD 154088 shines at apparent V-band magnitude 6.59 (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: La Silla Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 154088 |
| Spectral Type | K0 IV-V |
| Effective Temp (Teff) | 5,374 K |
| Stellar Radius | 0.9500 R☉ |
| Stellar Mass | 0.9100 M☉ |
| Bolometric Luminosity | 0.675 L☉ |
| Metallicity [Fe/H] | 0.280 dex |
| Stellar Age | 8.000 Gyr |
| Apparent Magnitude | V: 6.590 · G: 6.367 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.134000 AU |
| Orbital Period | 18.56 days |
| Mean Orbital Velocity | 78.5 km/s |
| Orbital Eccentricity (e) | 0.34400 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 2.44 g/cm³ (18.3 km/s vesc) |
| Insolation Flux | 41.2119 S⊕ (~56,089 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 59.600 LY (18.269 pc) |