HD 10180 e
Astrophysical Synthesis & Habitability Characterization
HD 10180 e is a confirmed sub-neptune exoplanet orbiting the star HD 10180, located approximately 127.1 light-years (38.96 parsecs) from the Solar System. First announced in 2010 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 5.39 Earth radii (0.48 Jupiter radii) and has a measured mass of 25.1 Earth masses. Combining its mass and radius yields a mean bulk density of 0.88 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.86 g⊕ (8.43 m/s²), and an escape velocity of 24.1 km/s.
In its orbital architecture around HD 10180, HD 10180 e completes one full revolution every 49.748 Earth days at a semi-major axis of 0.2699 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 59 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.051 carries the world between 0.2561 AU at periapsis and 0.2837 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 578 K (+305°C / +581°F) and receiving 20.45 S⊕ (~27,838 W/m²), HD 10180 e orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 10180 is classified as a solar-type yellow star of spectral type G1 V with an effective photospheric temperature of 5,911 K, a radius of 1.109 R☉, a mass of 1.06 M☉, an estimated bolometric luminosity of 1.347 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.3 Gyr and a metallicity of [Fe/H] = 0.08 dex (metal-rich relative to the Sun). From Earth, HD 10180 shines at apparent V-band magnitude 7.33 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The HD 10180 system is a multi-planet architecture hosting 6 confirmed worlds, with HD 10180 e sharing its stellar neighborhood alongside HD 10180 c, HD 10180 d, HD 10180 f, HD 10180 g, HD 10180 h.
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 10180 |
| Spectral Type | G1 V |
| Effective Temp (Teff) | 5,911 K |
| Stellar Radius | 1.1090 R☉ |
| Stellar Mass | 1.0600 M☉ |
| Bolometric Luminosity | 1.347 L☉ |
| Metallicity [Fe/H] | 0.080 dex |
| Stellar Age | 4.300 Gyr |
| Apparent Magnitude | V: 7.330 · G: 7.173 |
| System Architecture | 1 Star, 6 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.269900 AU |
| Orbital Period | 49.748 days |
| Mean Orbital Velocity | 59 km/s |
| Orbital Eccentricity (e) | 0.05100 |
| Orbital Inclination (i) | 90.0000° |
| Mean Bulk Density | 0.88 g/cm³ (24.1 km/s vesc) |
| Insolation Flux | 20.4541 S⊕ (~27,838 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 127.100 LY (38.961 pc) |