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Entering orbit…
Habitability
15/ 100
Uninhabitable

Sarnus

by Metamorphohedron1111
0

Gas Giant

Kerbol
Magnetic FieldExtreme Activity
Why is this a Gas Giant?Your planet has 81.7% hydrogen and helium, combined with a mass of 21.0x Earth, which exceeds the gas giant threshold.
Gas giants form when massive cores capture enormous atmospheres of light gases. They typically form beyond the 'frost line' where volatiles can condense.
Classification Criteria:
✓ Hydrogen + Helium: 81.7% (>60% required)✓ Mass: 21.0x Earth (>10x required)
Habitability ScoreUninhabitable
15
Contributing Factors
water15
No solid surface — any water is locked in a supercritical mantle and hot ice, not oceans
geology40
Extreme volcanic activity may be hazardous
rotation10
Near tidally locked - one hemisphere perpetually scorched, other frozen, narrow habitable twilight zone only
Organic Chemistry100
All CHNOPS elements present - building blocks of life (tidal pools cycle wet and dry - a boost for prebiotic chemistry)
atmosphere12
Hydrogen-rich atmosphere typical of gas giants (partially stripped by slow rotation)
temperature10
Frozen world - minimal potential for complex life
magnetic Field100
Magnetic field provides radiation protection

Physical Properties

Mass
21.00x Earth (1.25e+26 kg)
Radius
2.76x Earth (17,577 km)
This planet: 2.76× Earth radiusEarth: 1× (baseline)
Surface Gravity
2.76x Earth (27.1 m/s²)
Surface Temperature
91 K (-182 °C / -296 °F)
Rotation Period
9.0 hours/day (faster than Earth)
This planet: 9 h/dayEarth: 24 h/day

Orbital Environment

Star Type
G-type (Yellow (Sun-like))
Distance from Star
9.50 AU (1.42 billion km)
Orbital Period
29.3 years

Atmosphere

Hydrogen and helium dominated with trace methane and ammonia

Elemental Composition

H - Hydrogen
52.9%
He - Helium
28.8%
C - Carbon
5.8%

Surface Characteristics

No solid surface - thick gaseous envelope with possible rocky core deep within

Closest Real Exoplanet

GJ 687 c85% similar
Orbiting GJ 687
YoursGJ 687 c
Mass21.0 × Earth16.0 × Earth
Radius4.46 × Earth4.14 × Earth
Density (composition)1.30 g/cm³1.24 g/cm³
Temperature90.8 K99.0 K
Starlight received0.01 × Earth0.02 × Earth
Star temperature5,600 K3,413 K
Discovered 2020 via radial velocity · 15 light-years awaySource: NASA Exoplanet Archive
Moons
Moon 1rings0.095% - 2.2 radii

Inside the synchronous orbit: it spiraled inward and was torn apart at the Roche limit (Phobos's fate).

Moon 2stableOcean world0.010% - 7.9 radii

Small and distant: a quiet, stable companion.

A thin tidal-warmed subsurface ocean may exist, but conditions are marginal (2/100).

Moon 3stableOcean world0.045% - 11.7 radii

Small and distant: a quiet, stable companion.

A thin tidal-warmed subsurface ocean may exist, but conditions are marginal (3/100).

Moon 4stable0.040% - 27.2 radii

Small and distant: a quiet, stable companion.

Moon 5receding0.056% - 63.0 radii

Outside the synchronous orbit: slowly receding, like Luna (~cm per year).

+4 chemistry: tidal pools cycle wet and dry - a boost for prebiotic chemistry
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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