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Entering orbit…
Habitability
28/ 100
Extremely Harsh

G 9-40 b

BarrenExtremely Harsh91 light years awayFound 2019

G 9-40 b, from the NASA Exoplanet Archive (found 2019). Measured: 4 Earth masses, 0.0418 AU, a 3395 K M-type star. Composition inferred from a measured bulk density of 0.58x Earth's — too light for bare rock, so a large fraction of water and ice, with a day locked to its 5.8-day year, as anything orbiting this close would be.

Host star

G 9-40

Type
M-type (Red Dwarf)
Spectral type
M2.5 V
Temperature
3,395 K
Radius
0.303 ☉
Mass
0.295 ☉
Known planets
1 (this one)
Luminosity
0.0110 ☉

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.

Barren

High Activity
Why is this a Barren?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: 4.0x EarthTemperature: 474K
Further reading
The Little Book of ExoplanetsJoshua WinnHow these worlds are found, and what a measurement can honestly tell us.Exoplanets: Diamond Worlds, Super Earths, Pulsar PlanetsMichael Summers & James TrefilThe strange end of the catalogue — carbon worlds, molten rock, planets orbiting dead stars.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 ScoreExtremely Harsh
28
Contributing Factors
temperature15
Extremely hot - hostile to known life forms
atmosphere70
Nitrogen atmosphere provides protection but not breathable
water62
Abundant water - likely as steam
magnetic Field30
No magnetic field - vulnerable to solar radiation
geology90
Active geology recycles nutrients and drives carbon cycle
Organic Chemistry80
Core organic elements (CHNO) present
rotation30
Very slow rotation - extreme temperature swings between eternal day and night sides

Physical Properties

Mass
4.00x Earth (2.39e+25 kg)
Radius
1.59x Earth (10,113 km)
This planet: 1.59× Earth radiusEarth: 1× (baseline)
Surface Gravity
1.59x Earth (15.6 m/s²)
Surface Temperature
474 K (201 °C / 393 °F)
Rotation Period
138.0 hours/day (slower than Earth)
This planet: 138 h/dayEarth: 24 h/day

Orbital Environment

Star Type
M-type (Red Dwarf)
Distance from Star
0.04 AU (6.25 million km)
Orbital Period
6 days

Atmosphere

Thin CO₂ and nitrogen atmosphere

Elemental Composition

O - Oxygen
41.2%
H - Hydrogen
17.6%
Si - Silicon
11.8%

Surface Characteristics

Barren rocky surface with unusual elemental composition
The TerraForge exoplanet catalog: 5,572 real exoplanets run through the simulation, with a search field and rendered worlds grouped by type

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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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