AU Mic e
Astrophysical Synthesis & Habitability Characterization
AU Mic e is a confirmed sub-neptune exoplanet orbiting the star AU Mic, located approximately 31.7 light-years (9.72 parsecs) from the Solar System. First announced in 2025 by Mauna Kea Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 4.87 Earth radii (0.43 Jupiter radii) and has a measured mass of 21.1 Earth masses. Combining its mass and radius yields a mean bulk density of 1.01 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.89 g⊕ (8.73 m/s²), and an escape velocity of 23.3 km/s.
In its orbital architecture around AU Mic, AU Mic e completes one full revolution every 33.11 Earth days.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 4.870 R⊕, AU Mic e exceeds the empirical ~1.8–2.2 R⊕ Fulton radius valley threshold, indicating a substantial hydrogen-helium or supercritical volatile envelope without a conventional solid terrestrial surface.
The host star AU Mic is classified as a low-mass red dwarf of spectral type M1 V with an effective photospheric temperature of 3,665 K, a radius of 0.82 R☉, a mass of 0.6 M☉, an estimated bolometric luminosity of 0.109 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.019 Gyr and a metallicity of [Fe/H] = 0.12 dex (metal-rich relative to the Sun). From Earth, AU Mic shines at apparent V-band magnitude 8.81 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The AU Mic system is a multi-planet architecture hosting 4 confirmed worlds, with AU Mic e sharing its stellar neighborhood alongside AU Mic b, AU Mic d, AU Mic 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: Mauna Kea Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | AU Mic |
| Spectral Type | M1 V |
| Effective Temp (Teff) | 3,665 K |
| Stellar Radius | 0.8200 R☉ |
| Stellar Mass | 0.6000 M☉ |
| Bolometric Luminosity | 0.109 L☉ |
| Metallicity [Fe/H] | 0.120 dex |
| Stellar Age | 0.019 Gyr |
| Apparent Magnitude | V: 8.810 · G: 7.840 |
| System Architecture | 1 Star, 4 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | — |
| Orbital Period | 33.11 days |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.01 g/cm³ (23.3 km/s vesc) |
| Insolation Flux | — |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 31.700 LY (9.722 pc) |