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Entering orbit…
Habitability
10/ 100
Uninhabitable

AU Mic b

Gas DwarfUninhabitable32 light years awayFound 2020

AU Mic b, from the NASA Exoplanet Archive (found 2020). Measured: 8.99 Earth masses, 0.07 AU, a 3540 K M-type star. Composition inferred from a measured bulk density of 0.08x Earth's, which only hydrogen and helium can explain, with a day locked to its 8.5-day year, as anything orbiting this close would be.

Host star

AU Mic

Type
M-type (Red Dwarf)
Spectral type
M1 V
Temperature
3,540 K
Radius
0.862 ☉
Mass
0.635 ☉
Known planets
4, including this one
Luminosity
0.105 ☉

Published by the NASA Exoplanet Archive. This world’s temperature and habitability score are computed from this star’s measured luminosity, not from a stand-in for its class.

Gas Dwarf

Low Activity
Why is this a Gas Dwarf?Your planet has an unusual composition that doesn't fit standard classifications, or lacks the elements needed for complex geological processes.
Barren worlds can form from uncommon element combinations or may be remnants of larger bodies that lost their atmospheres and volatile materials.
Classification Criteria:
Composition doesn't match standard planet typesMass: 9.0x EarthTemperature: 600K
Further reading
Exoplanets: Diamond Worlds, Super Earths, Pulsar PlanetsMichael Summers & James TrefilThe strange end of the catalogue — carbon worlds, molten rock, planets orbiting dead stars.The Little Book of ExoplanetsJoshua WinnHow these worlds are found, and what a measurement can honestly tell us.Envisioning ExoplanetsMichael CarrollWhat these worlds might look like from the ground, painted from the same measurements this page renders.Imagined LifeJames Trefil & Michael SummersWhat could live on a world like this one: ice shells, supergravity, tidally locked twilight.
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Habitability ScoreUninhabitable
10
Contributing Factors
temperature15
Extremely hot - hostile to known life forms
atmosphere18
Hydrogen-rich atmosphere typical of gas giants (partially stripped by slow rotation)
water15
No solid surface — any water is locked in a supercritical mantle and hot ice, not oceans
magnetic Field30
No magnetic field - vulnerable to solar radiation
geology60
Some geological activity provides slow nutrient cycling
Organic Chemistry80
Core organic elements (CHNO) present
rotation30
Very slow rotation - extreme temperature swings between eternal day and night sides

Physical Properties

Mass
8.99x Earth (5.37e+25 kg)
Radius
2.08x Earth (13,247 km)
This planet: 2.08× Earth radiusEarth: 1× (baseline)
Surface Gravity
2.08x Earth (20.4 m/s²)
Surface Temperature
600 K (326 °C / 620 °F)
Rotation Period
203.0 hours/day (slower than Earth)
This planet: 203 h/dayEarth: 24 h/day

Orbital Environment

Star Type
M-type (Red Dwarf)
Distance from Star
0.07 AU (10.5 million km)
Orbital Period
12 days

Atmosphere

Deep hydrogen-helium envelope with photochemical haze

Elemental Composition

H - Hydrogen
53.8%
He - Helium
32.3%
O - Oxygen
5.4%

Surface Characteristics

No solid surface - a thick gas envelope wrapped around a small deep core (a mini-Neptune)
The TerraForge exoplanet catalog: 5,572 real exoplanets run through the simulation, with a search field and rendered worlds grouped by type

New: The Exoplanet Catalog 🔭

Every confirmed planet NASA has measured well enough to build — 5,572 of them — is now in here, and none of them arrived with a label. Their real mass, radius, orbit and star go through the same simulation that runs everything you make, and it decides what each one is: gas giant, lava world, ocean, ice. Sixteen come out Earth-like. Find TRAPPIST-1e, stand on its surface, and see what a red dwarf's light actually looks like from the ground.

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