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Entering orbit…
Habitability
10/ 100
Uninhabitable

HIP 9618 b

Gas DwarfUninhabitable220 light years awayFound 2023

HIP 9618 b, from the NASA Exoplanet Archive (found 2023). Measured: 8.3 Earth masses, 0.145 AU, a 5649 K G-type star. Composition inferred from a measured bulk density of 0.15x Earth's, which only hydrogen and helium can explain, with an assumed 24-hour day — rotation cannot be measured for exoplanets.

Host star

HIP 9618

Type
G-type (Yellow (Sun-like))
Temperature
5,649 K
Radius
0.959 ☉
Mass
0.942 ☉
Known planets
2, including this one
Luminosity
0.848 ☉

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 Dwarf

Magnetic FieldLow Activity
Why is this a Gas Dwarf?Your planet has an unusual composition that doesn't fit standard classifications, or lacks the elements needed for complex geological processes.
Barren worlds can form from uncommon element combinations or may be remnants of larger bodies that lost their atmospheres and volatile materials.
Classification Criteria:
Composition doesn't match standard planet typesMass: 8.3x EarthTemperature: 702K
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
10
Contributing Factors
temperature5
Scorching - hot enough to melt lead, though rock stays solid; no chance for 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
geology60
Some geological activity provides slow nutrient cycling
Organic Chemistry80
Core organic elements (CHNO) present
rotation100
Optimal rotation period - balanced day/night cycle, moderate weather, and good heat distribution

Physical Properties

Mass
8.30x Earth (4.96e+25 kg)
Radius
2.02x Earth (12,899 km)
This planet: 2.02× Earth radiusEarth: 1× (baseline)
Surface Gravity
2.02x Earth (19.9 m/s²)
Surface Temperature
702 K (429 °C / 804 °F)
Rotation Period
24.0 hours/day
This planet: 24 h/dayEarth: 24 h/day

Orbital Environment

Star Type
G-type (Yellow (Sun-like))
Distance from Star
0.14 AU (21.7 million km)
Orbital Period
20 days

Atmosphere

Deep hydrogen-helium envelope with photochemical haze

Elemental Composition

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

Surface Characteristics

No solid surface - a thick gas envelope wrapped around a small deep core (a mini-Neptune)
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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