HD 140901 b
Astrophysical Synthesis & Habitability Characterization
HD 140901 b is a confirmed sub-neptune exoplanet orbiting the star HD 140901, located approximately 49.7 light-years (15.25 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 4.07 Earth radii (0.36 Jupiter radii) and has a measured mass of 15.574 Earth masses. Combining its mass and radius yields a mean bulk density of 1.27 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 21.9 km/s.
In its orbital architecture around HD 140901, HD 140901 b completes one full revolution every 9.024 Earth days at a semi-major axis of 0.085 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 102.5 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.472, swinging from 0.0449 AU at periapsis out to 0.1251 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 904 K (+631°C / +1168°F) and receiving 109.34 S⊕ (~148,815 W/m²), HD 140901 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 140901 is classified as a solar-type yellow star of spectral type G7 IV with an effective photospheric temperature of 5,610 K, a radius of 0.95 R☉, a mass of 0.99 M☉, an estimated bolometric luminosity of 0.802 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.2 Gyr and a metallicity of [Fe/H] = 0.086 dex (metal-rich relative to the Sun). From Earth, HD 140901 shines at apparent V-band magnitude 6.01 (visible to the unaided human eye under dark skies) in the Southern celestial hemisphere. The HD 140901 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 140901 b sharing its stellar neighborhood alongside HD 140901 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 140901 |
| Spectral Type | G7 IV |
| Effective Temp (Teff) | 5,610 K |
| Stellar Radius | 0.9500 R☉ |
| Stellar Mass | 0.9900 M☉ |
| Bolometric Luminosity | 0.802 L☉ |
| Metallicity [Fe/H] | 0.086 dex |
| Stellar Age | 3.200 Gyr |
| Apparent Magnitude | V: 6.010 · G: 5.831 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.085000 AU |
| Orbital Period | 9.024 days |
| Mean Orbital Velocity | 102.5 km/s |
| Orbital Eccentricity (e) | 0.47200 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.27 g/cm³ (21.9 km/s vesc) |
| Insolation Flux | 109.3426 S⊕ (~148,815 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 49.700 LY (15.253 pc) |