HD 156098 b
Astrophysical Synthesis & Habitability Characterization
HD 156098 b is a confirmed sub-neptune exoplanet orbiting the star HD 156098, located approximately 157.4 light-years (48.25 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 4.12 Earth radii (0.37 Jupiter radii) and has a measured mass of 15.891 Earth masses. Combining its mass and radius yields a mean bulk density of 1.25 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.94 g⊕ (9.22 m/s²), and an escape velocity of 22 km/s.
In its orbital architecture around HD 156098, HD 156098 b completes one full revolution every 21.858 Earth days at a semi-major axis of 0.167 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 83.1 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.109 carries the world between 0.1488 AU at periapsis and 0.1852 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1258 K (+985°C / +1805°F) and receiving 416.97 S⊕ (~567,500 W/m²), HD 156098 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 156098 is classified as a stellar host with an effective photospheric temperature of 6,419 K, a radius of 2.7572 R☉, a mass of 1.29 M☉, an estimated bolometric luminosity of 11.58 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.12 dex (metal-rich relative to the Sun). From Earth, HD 156098 shines at apparent V-band magnitude 5.53 (visible to the unaided human eye under dark skies) in the Southern celestial hemisphere. The HD 156098 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 156098 b sharing its stellar neighborhood alongside HD 156098 c.
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 156098 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,419 K |
| Stellar Radius | 2.7572 R☉ |
| Stellar Mass | 1.2900 M☉ |
| Bolometric Luminosity | 11.58 L☉ |
| Metallicity [Fe/H] | 0.120 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 5.530 · G: 5.412 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.167000 AU |
| Orbital Period | 21.858 days |
| Mean Orbital Velocity | 83.1 km/s |
| Orbital Eccentricity (e) | 0.10900 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.25 g/cm³ (22 km/s vesc) |
| Insolation Flux | 416.9726 S⊕ (~567,500 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 157.400 LY (48.249 pc) |