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Entering orbit…
Habitability
19/ 100
Uninhabitable
GJ 3323 c rendered in TerraForge from its measured mass, orbit and star

GJ 3323 c

Also written GJ 3323c

Ice World18 light years awayFound 2017
Mass
2.31 × Earth
Radius
1.32 × Earth
Gravity
1.33 g
Surface (est.)
181 K
Year
40.5 days
From Earth
17.5 ly
Mass
2.31 × Earth
Radius
1.32 × Earth
Gravity
1.33 g
Surface (est.)
181 K
Year
40.5 days
From Earth
17.5 ly

GJ 3323 system

Type
M-type (Red Dwarf)
Spectral type
M4
Temperature
3,159 K
Radius
0.119 ☉
Mass
0.164 ☉
Planets
2
Luminosity
2.70e-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.

GJ 3323 b0.033 AU2.0 M⊕
GJ 3323 c0.13 AUYou are here2.3 M⊕
Habitable zone

Star and planets drawn to scale: the star is 9.8 times as wide as GJ 3323 c, so only its edge is in view. Orbits spaced as in the star system view.

Estimated: this planet doesn't transit its star, so its size is inferred, not measured

GJ 3323 c, from the NASA Exoplanet Archive (found 2017). Measured: 2.31 Earth masses, 0.126 AU, a 3159 K M-type star. Composition inferred from an estimated bulk density of 1.00x Earth's, modeled rather than measured since this isn't a transiting planet — the radius is the archive's estimate, so it can't settle how much water there is; read as rock and iron, with an assumed 24-hour day — rotation cannot be measured for exoplanets.

Surface. Frozen surface covered in water ice, possible subsurface ocean if tidal heating present

Ice World
Life unlikely — too cold for liquid waterMagnetic FieldHigh Activity
GJ 3323 c orbits at 0.13 AU from its star, resulting in frigid temperatures of 181K.
Ice worlds form beyond the frost line where temperatures are low enough for water and other volatiles to freeze solid. They may have subsurface oceans beneath thick ice shells.
Classification Criteria:
✓ Distance: 0.13 AU (>3 AU) or Temperature <200K✓ Temperature: 181K✓ Water content: 34.4% for ice formation

Reading GJ 3323 c’s atmosphere

Dominant elements: O, Si, Fe, N, C, HThis is what a telescope would measure while GJ 3323 c crosses in front of its star: starlight passes through the atmosphere and spreads into a rainbow band. Each dark line marks a wavelength the atmosphere absorbed.Every element absorbs its own signature wavelengths — hydrogen always darkens the same two spots, calcium another pair, and so on. Astronomers match the lines in a real spectrum against a library of these signatures to say what an atmosphere is made of, light-years away, without ever visiting. A deeper line generally means more of that element is present.GJ 3323 c sits about 18 light-years away, found by the radial velocity method. Most catalogued distances trace back to parallax: as Earth orbits the Sun, a nearby star appears to shift very slightly against the distant background stars, and the size of that shift gives its distance directly.
Further reading
ExoplanetsSara Seager (editor)The field's standard reference: how planets are found, how they form, and what their atmospheres are made of.The Planet FactoryElizabeth TaskerHow planets are made, and why so few of them come out like Earth.Imagined LifeJames Trefil & Michael SummersWhat could live on a world like this one: ice shells, supergravity, tidally locked twilight.Envisioning ExoplanetsMichael CarrollWhat these worlds might look like from the ground, painted from the same measurements this page renders.
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Habitability ScoreUninhabitable
19
Contributing Factors
temperature18
Very cold - water frozen, challenging for life
atmosphere70

Thin nitrogen and methane atmosphere

Nitrogen atmosphere provides protection but not breathable
water11
Limited water content - frozen solid, no liquid phase at this temperature
magnetic Field100
Magnetic field provides radiation protection
geology90
Active geology recycles nutrients and drives carbon cycle
Organic Chemistry80
Core organic elements (CHNO) present
rotation100
Optimal rotation period - balanced day/night cycle, moderate weather, and good heat distribution

Physical Properties

Mass
2.31x Earth (1.38e+25 kg)
Radius
1.32x Earth (8,422 km)
This planet: 1.32× Earth radiusEarth: 1× (baseline)
Surface Gravity
1.32x Earth (13.0 m/s²)
Surface Temperature
181 K (-92 °C / -134 °F)
Rotation Period
24.0 hours/day
This planet: 24 h/dayEarth: 24 h/day

Elemental Composition

A dark ringed planet hanging over the horizon of a rocky moon, its rings lit by a distant sun

New: Stand on Your Moons 🌒

A planet's surface view isn't the only ground any more. Press the surface button on a planet with moons and it asks where to stand: the planet itself, or any moon still in orbit, each tagged with what it became — ocean, ice, carbon, volcanic. Every moon gets its own ground and sky from its own physics: airless rock under a black sky, ice cracked by geysers over a hidden sea, sulfur plains shaking with eruptions, or orange haze you can't see the sun through. And hanging over the horizon, there's the planet you built.

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