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Entering orbit…
Habitability
6/ 100
Uninhabitable

GJ 238 b

BarrenUninhabitable50 light years awayFound 2024

GJ 238 b, from the NASA Exoplanet Archive (found 2024). Measured: 0.126 Earth masses, 0.0212 AU, a 3485 K M-type star. Composition inferred from a measured bulk density of 0.69x Earth's — too light for bare rock, so a large fraction of water and ice, with a day locked to its 1.7-day year, as anything orbiting this close would be.

Host star

GJ 238

Type
M-type (Red Dwarf)
Spectral type
M2.5 V
Temperature
3,485 K
Radius
0.431 ☉
Mass
0.419 ☉
Known planets
1 (this one)
Luminosity
0.0242 ☉

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

None 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: 0.1x EarthTemperature: 753K
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 ScoreUninhabitable
6
Contributing Factors
temperature5
Scorching - hot enough to melt lead, though rock stays solid; no chance for life
atmosphere10
No atmosphere - exposed to radiation and temperature extremes
water15
Abundant water - boiling away, little would be retained
magnetic Field30
No magnetic field - vulnerable to solar radiation
geology30
Geologically dead - no nutrient recycling
Organic Chemistry80
Core organic elements (CHNO) present
rotation65
Slow rotation - significant day/night temperature variations, but life can adapt

Physical Properties

Mass
0.13x Earth (7.52e+23 kg)
Radius
0.50x Earth (3,194 km)
This planet: 0.50× Earth radiusEarth: 1× (baseline)
Surface Gravity
0.50x Earth (4.9 m/s²)
Surface Temperature
753 K (480 °C / 896 °F)
Rotation Period
41.8 hours/day (slower than Earth)
This planet: 42 h/dayEarth: 24 h/day

Orbital Environment

Star Type
M-type (Red Dwarf)
Distance from Star
0.02 AU (3.17 million km)
Orbital Period
2 days
Time Dilation
Clocks run 6.6 seconds per year slower than deep space — about 9 minutes over a lifetime

Atmosphere

None

Elemental Composition

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

Surface Characteristics

Barren rocky surface with unusual elemental composition
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