NASA (Exoplanet Catalog artwork)AU Microscopii b
A newborn Neptune around a flaring star with a dusty disk, just 32 light-years away
Overview
AU Microscopii b is a Neptune-like exoplanet that orbits a M-type star. Its mass is 8.99 Earths, it takes 8.5 days to complete one orbit of its star, and is 0.07 AU from its star. Its discovery was announced in 2020.
Source: NASA Exoplanet Catalog
Why it matters
- Found by TESS and Spitzer in 2020 around a 22-million-year-old red dwarf.
- Its star's debris disk is one of the most studied, with fast-moving dust clumps.
- A rare chance to watch a young planet's atmosphere being eroded in real time.
NASA puts it this way: “Located less than 32 light-years from Earth, AU Microscopii is among the youngest planetary systems ever observed by astronomers, and its star throws vicious temper tantrums! ”
Discovery & system
- Discovered
- 2020 · Transit · Transiting Exoplanet Survey Satellite (TESS)
- Discovery paper
- Plavchan et al. 2020
- Host star
- AU Mic · M1 V · 3,540 K · 0.64 M☉
- System
- 4 known planets
- Siblings
- AU Mic d, AU Mic e, AU Mic c
The system
| World | Period | Distance | Radius | Mass | Temp. |
|---|---|---|---|---|---|
| AU Mic b | 8.46 d | 0.07 AU | 0.43 R♃ | 8.99 M⊕ | 555 K |
| AU Mic d | 12.7 d | 0.092 AU | 1.02 R⊕ | 1.05 M⊕ | — |
| AU Mic c | 18.9 d | 0.119 AU | 2.79 R⊕ | 14.46 M⊕ | 425 K |
| AU Mic e ? | 33.1 d | 0.173 AU | 0.43 R♃ | 21.1 M⊕ | — |
this worldhabitable zone 0.308 AU – 0.542 AUlog distance scaleorbital phases are arbitrarystar: M1 V, 3,540 K
By the numbers
- Radius
- 0.43 R♃4.8 R⊕
- Mass
- 8.99 M⊕53.69 ×10²⁴ kg
- Orbital period
- 8.46 d0.02 yr
- Distance from star
- 0.07 AU10.47 million km
- Eccentricity
- 0.07elliptical
- Equilibrium temp.
- 555 K282 °C
- Starlight received
- 21 × Earth
- Distance from Earth
- 31.7 ly9.7 pc
- Density
- 0.49 g/cm³0.09 × Earth
Sources
Image: NASA (Exoplanet Catalog artwork) · NASA media: generally free of copyright · image page
Text: NASA Exoplanet Catalog. Taglines and highlights are editorial.