Create your free account

Enter your email and we'll send a 6-digit code — no password needed.
We only keep your email and the username you choose. We never share or sell your email, and we don't send marketing — we use it only to email you a sign-in code. Learn more.
Entering orbit…
Habitability
0/ 100
Uninhabitable

Kepler-9 d

Gas GiantUninhabitable2047 light years awayFound 2010

Kepler-9 d, from the NASA Exoplanet Archive (found 2010). Measured: 8.41 Earth masses, 0.0273 AU, a 5777 K G-type star. Composition inferred from a measured bulk density of 1.91x Earth's, far too high for silicates alone — an iron-rich world, with a day locked to its 1.6-day year, as anything orbiting this close would be.

Host star

Kepler-9

Type
G-type (Yellow (Sun-like))
Temperature
5,777 K
Radius
1.02 ☉
Mass
1.07 ☉
Known planets
3, including this one
Luminosity
0.916 ☉

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 0.0% hydrogen and helium, combined with a mass of 8.4x 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: 0.0% (>60% required)✓ Mass: 8.4x 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.
As an Amazon Associate I earn from qualifying purchases — if you buy through these links, TerraForge may receive a small commission at no extra cost to you.
Habitability ScoreUninhabitable
0
Contributing Factors
temperature0
Inferno world - temperatures exceed all possibility of life
atmosphere30
Hydrogen-rich atmosphere typical of gas giants
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 Chemistry20
Limited organic chemistry potential
rotation100
Optimal rotation period - balanced day/night cycle, moderate weather, and good heat distribution

Physical Properties

Mass
8.41x Earth (5.02e+25 kg)
Radius
2.03x Earth (12,956 km)
This planet: 2.03× Earth radiusEarth: 1× (baseline)
Surface Gravity
2.03x Earth (19.9 m/s²)
Surface Temperature
1,646 K (1,373 °C / 2,503 °F)
Rotation Period
38.2 hours/day (slower than Earth)
This planet: 38 h/dayEarth: 24 h/day

Orbital Environment

Star Type
G-type (Yellow (Sun-like))
Distance from Star
0.03 AU (4.08 million km)
Orbital Period
2 days
Time Dilation
Clocks run 17.1 seconds per year slower than deep space — about 23 minutes over a lifetime

Atmosphere

Hydrogen and helium dominated with trace methane and ammonia

Elemental Composition

Si - Silicon
36.6%
Fe - Iron
24.4%
Mg - Magnesium
12.2%

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.

Create your free account

Enter your email and we'll send a 6-digit code — no password needed.
We only keep your email and the username you choose. We never share or sell your email, and we don't send marketing — we use it only to email you a sign-in code. Learn more.

Send feedback

We're still building out the best experience we can — and we'd love your input. Tell us about features you enjoy, ideas you'd like to see, or pain points where something feels off, and we'll know where to look next.

Type