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Entering orbit…
Habitability
30/ 100
Extremely Harsh

Diamond Planet I

by Stargazer
0

Carbon World

Magnetic FieldModerate Activity
Why is this a Carbon World?Your planet's carbon (40.9%) outweighs its oxygen (8.2%), so the mineralogy flips from silicate rock to carbide - a graphite crust over a diamond mantle.
Carbon worlds form in carbon-rich disks where there isn't enough oxygen to bind it all into silicates. Instead carbon condenses directly into graphite, carbides, and - under pressure at depth - diamond. They form water-poor, so no life takes hold.
Classification Criteria:
✓ Carbon: 40.9% (>=20% required)✓ Carbon exceeds Oxygen: 40.9% > 8.2%✓ Mass: 1.8x Earth (<=8x hycean ceiling)
Habitability ScoreExtremely Harsh
30
Contributing Factors
water50
Water present but likely as steam
geology90
Active geology recycles nutrients and drives carbon cycle
rotation100
Optimal rotation period - balanced day/night cycle, moderate weather, and good heat distribution
Organic Chemistry80
Core organic elements (CHNO) present
atmosphere40
Atmosphere present but composition not ideal for life
temperature15
Extremely hot - hostile to known life forms
magnetic Field100
Magnetic field provides radiation protection

Physical Properties

Mass
1.80x Earth (1.07e+25 kg)
Radius
1.22x Earth (7,750 km)
This planet: 1.22× Earth radiusEarth: 1× (baseline)
Surface Gravity
1.22x Earth (11.9 m/s²)
Surface Temperature
511 K (238 °C / 461 °F)
Rotation Period
20.0 hours/day (faster than Earth)
This planet: 20 h/dayEarth: 24 h/day

Orbital Environment

Star Type
G-type (Yellow (Sun-like))
Distance from Star
0.80 AU (120 million km)
Orbital Period
261 days

Atmosphere

Carbon monoxide and methane haze over a graphite surface

Elemental Composition

C - Carbon
40.9%
Fe - Iron
13.6%
Si - Silicon
13.6%

Surface Characteristics

Graphite plains and carbide ridges over a diamond mantle - a glittering coal-black world

Closest Real Exoplanet

Kepler-1512 b85% similar
Orbiting Kepler-1512
YoursKepler-1512 b
Mass1.80 × Earth1.76 × Earth
Radius1.32 × Earth1.18 × Earth
Density (composition)4.36 g/cm³5.90 g/cm³
Temperature511.3 K322.0 K
Starlight received1.56 × Earth1.60 × Earth
Star temperature5,600 K4,372 K
Discovered 2016 via transit · 528 light-years awaySource: NASA Exoplanet Archive
Surface views from three worlds: rocky ground under a ringed sky, a cloud deck, and a lit desert

New: Stand on Your World 🏔️

Every planet you build can now be seen from the ground. The terrain, the color of the sky, the weather and what hangs overhead are all read from the same numbers that shape the globe — so a thin-aired world gives you sunlit rock under a near-black sky crowded with stars, a runaway greenhouse seals you under an unbroken sulfur lid, and a gas giant leaves you in the cloud tops with nothing solid beneath you at all. If one of your moons wandered inside the Roche limit, what is left of it arcs overhead as rings.

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