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Entering orbit…
Habitability
42/ 100
Marginal

GJ 3378 b

Rocky TerrestrialMarginal25 light years awayFound 2026

GJ 3378 b, from the NASA Exoplanet Archive (found 2026). Measured: 2.3 Earth masses, 0.0967 AU, a 3340 K M-type star. Composition inferred from a measured bulk density of 1.00x Earth's, which is rock and iron, with a day locked to its 21.4-day year, as anything orbiting this close would be.

Host star

GJ 3378

Type
M-type (Red Dwarf)
Spectral type
M4 V
Temperature
3,340 K
Radius
0.275 ☉
Mass
0.262 ☉
Known planets
1 (this one)
Luminosity
8.50e-3 ☉

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.

Rocky Terrestrial

Life DetectedHigh Activity
Why is this a Rocky Terrestrial?Your planet is dominated by silicate (25.0%) and iron (12.5%) content, forming a rocky terrestrial body.
Rocky terrestrial planets are primarily composed of silicate rocks and metals. They're the most common type of small planet in the universe.
Classification Criteria:
✓ Silicon: 25.0% + Iron: 12.5% + Magnesium: 3.8%✓ Mass: 2.3x Earth (terrestrial range)
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 ScoreMarginal
42
Contributing Factors
temperature100
Optimal temperature range for liquid water and life
atmosphere28
Nitrogen atmosphere provides protection but not breathable (partially stripped by slow rotation)
water50
Limited water content
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
rotation10
Near tidally locked - one hemisphere perpetually scorched, other frozen, narrow habitable twilight zone only

Physical Properties

Mass
2.30x Earth (1.37e+25 kg)
Radius
1.32x Earth (8,410 km)
This planet: 1.32× Earth radiusEarth: 1× (baseline)
Surface Gravity
1.32x Earth (12.9 m/s²)
Surface Temperature
275 K (2 °C / 36 °F)
Rotation Period
513.6 hours/day (slower than Earth)
This planet: 514 h/dayEarth: 24 h/day

Orbital Environment

Star Type
M-type (Red Dwarf)
Distance from Star
0.10 AU (14.5 million km)
Orbital Period
20 days

Atmosphere

Thin CO₂ and nitrogen atmosphere

Elemental Composition

O - Oxygen
31.3%
Si - Silicon
25.0%
Fe - Iron
12.5%

Surface Characteristics

Rocky surface with impact craters, possible volcanic features

Habitability

✓ Conditions suitable for life detectedThis planet exhibits the necessary conditions to support biological processes, including stable temperatures, liquid water, and protective magnetic fields.
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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