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Entering orbit…
Habitability
12/ 100
Uninhabitable

TOI-6303 b

Gas GiantUninhabitable496 light years awayFound 2025

TOI-6303 b, from the NASA Exoplanet Archive (found 2025). Measured: 2490 Earth masses, 0.0761 AU, a 3977 K K-type star. Composition inferred from a mass of 2490 Earths, which is giant territory whatever its 1.60x density suggests, with a day locked to its 9.5-day year, as anything orbiting this close would be.

Host star

TOI-6303

Type
K-type (Orange)
Temperature
3,977 K
Radius
0.609 ☉
Mass
0.644 ☉
Known planets
1 (this one)
Luminosity
0.0819 ☉

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.

Gas Giant

Magnetic FieldExtreme Activity
Why is this a Gas Giant?Your planet has 86.0% hydrogen and helium, combined with a mass of 2490.0x 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: 86.0% (>60% required)✓ Mass: 2490.0x Earth (>10x required)
Further reading
Exoplanets: Diamond Worlds, Super Earths, Pulsar PlanetsMichael Summers & James TrefilThe strange end of the catalogue — carbon worlds, molten rock, planets orbiting dead stars.The Little Book of ExoplanetsJoshua WinnHow these worlds are found, and what a measurement can honestly tell us.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
12
Contributing Factors
temperature15
Extremely hot - hostile to known life forms
atmosphere18
Hydrogen-rich atmosphere typical of gas giants (partially stripped by slow rotation)
water15
No solid surface — any water is locked in a supercritical mantle and hot ice, not oceans
magnetic Field100
Magnetic field provides radiation protection
geology40
Extreme volcanic activity may be hazardous
Organic Chemistry80
Core organic elements (CHNO) present
rotation30
Very slow rotation - extreme temperature swings between eternal day and night sides

Physical Properties

Mass
2490.00x Earth (1.49e+28 kg)
Radius
13.55x Earth (86,352 km)
This planet: 13.55× Earth radiusEarth: 1× (baseline)
Surface Gravity
13.55x Earth (133.0 m/s²)
Surface Temperature
540 K (267 °C / 513 °F)
Rotation Period
227.8 hours/day (slower than Earth)
This planet: 228 h/dayEarth: 24 h/day

Orbital Environment

Star Type
K-type (Orange)
Distance from Star
0.08 AU (11.4 million km)
Orbital Period
9 days

Atmosphere

Hydrogen and helium dominated with trace methane and ammonia

Elemental Composition

H - Hydrogen
53.8%
He - Helium
32.3%
O - Oxygen
5.4%

Surface Characteristics

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