AU Mic c
Astrophysical Synthesis & Habitability Characterization
AU Mic c 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 2021 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.0881% across the stellar disk), this world measures 2.79 Earth radii and has a measured mass of 14.46 Earth masses. Combining its mass and radius yields a mean bulk density of 3.67 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.86 g⊕ (18.24 m/s²), and an escape velocity of 25.5 km/s.
In its orbital architecture around AU Mic, AU Mic c completes one full revolution every 18.859 Earth days at a semi-major axis of 0.119 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 68.6 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.18 carries the world between 0.0976 AU at periapsis and 0.1404 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 425 K (+152°C / +306°F) and receiving 7.30 S⊕ (~9,935 W/m²), AU Mic c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star AU Mic is classified as a low-mass red dwarf of spectral type M1 V with an effective photospheric temperature of 3,540 K, a radius of 0.862 R☉, a mass of 0.635 M☉, an estimated bolometric luminosity of 0.105 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.019 Gyr and a metallicity of [Fe/H] = 0.01 dex (near-solar heavy-element abundance). 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 c sharing its stellar neighborhood alongside AU Mic b, AU Mic d, AU Mic e.
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: Transiting Exoplanet Survey Satellite (TESS) · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | AU Mic |
| Spectral Type | M1 V |
| Effective Temp (Teff) | 3,540 K |
| Stellar Radius | 0.8620 R☉ |
| Stellar Mass | 0.6350 M☉ |
| Bolometric Luminosity | 0.105 L☉ |
| Metallicity [Fe/H] | 0.010 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) | 0.119000 AU |
| Orbital Period | 18.859 days |
| Mean Orbital Velocity | 68.6 km/s |
| Orbital Eccentricity (e) | 0.18000 |
| Orbital Inclination (i) | 89.4600° |
| Mean Bulk Density | 3.67 g/cm³ (25.5 km/s vesc) |
| Insolation Flux | 7.3000 S⊕ (~9,935 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 31.700 LY (9.722 pc) |