HD 3167 e
Astrophysical Synthesis & Habitability Characterization
HD 3167 e is a confirmed sub-neptune exoplanet orbiting the star HD 3167, located approximately 154.2 light-years (47.29 parsecs) from the Solar System. First announced in 2022 by CHaracterising ExOPlanets Satellite (CHEOPS) using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 3.97 Earth radii (0.35 Jupiter radii) and has a measured mass of 14.9 Earth masses. Combining its mass and radius yields a mean bulk density of 1.31 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.95 g⊕ (9.32 m/s²), and an escape velocity of 21.7 km/s.
In its orbital architecture around HD 3167, HD 3167 e completes one full revolution every 91.9 Earth days at a semi-major axis of 0.3797 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 44.9 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.128 carries the world between 0.3311 AU at periapsis and 0.4283 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 389 K (+116°C / +241°F) and receiving 3.84 S⊕ (~5,220 W/m²), HD 3167 e orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 3167 is classified as an orange K-type star of spectral type K0 V with an effective photospheric temperature of 5,338 K, a radius of 0.871 R☉, a mass of 0.864 M☉, an estimated bolometric luminosity of 0.553 L☉. Stellar evolution modeling indicates an estimated stellar age of 8.4 Gyr and a metallicity of [Fe/H] = 0.037 dex (near-solar heavy-element abundance). From Earth, HD 3167 shines at apparent V-band magnitude 8.97 (accessible to binoculars and small amateur telescopes) in the Northern celestial hemisphere. The HD 3167 system is a multi-planet architecture hosting 4 confirmed worlds, with HD 3167 e sharing its stellar neighborhood alongside HD 3167 b, HD 3167 d, HD 3167 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: CHaracterising ExOPlanets Satellite (CHEOPS) · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 3167 |
| Spectral Type | K0 V |
| Effective Temp (Teff) | 5,338 K |
| Stellar Radius | 0.8710 R☉ |
| Stellar Mass | 0.8640 M☉ |
| Bolometric Luminosity | 0.553 L☉ |
| Metallicity [Fe/H] | 0.037 dex |
| Stellar Age | 8.400 Gyr |
| Apparent Magnitude | V: 8.970 · G: 8.762 |
| System Architecture | 1 Star, 4 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.379700 AU |
| Orbital Period | 91.9 days |
| Mean Orbital Velocity | 44.9 km/s |
| Orbital Eccentricity (e) | 0.12800 |
| Orbital Inclination (i) | 41.0000° |
| Mean Bulk Density | 1.31 g/cm³ (21.7 km/s vesc) |
| Insolation Flux | 3.8357 S⊕ (~5,220 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 154.200 LY (47.290 pc) |