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
30/ 100
Extremely Harsh

HD 180617 b

Ice GiantExtremely Harsh19 light years awayFound 2018

HD 180617 b, from the NASA Exoplanet Archive (found 2018). Measured: 12.2 Earth masses, 0.343 AU, a 3534 K M-type star. Composition inferred from a measured bulk density of 0.28x Earth's — too light for bare rock, so a large fraction of water and ice, with an assumed 24-hour day — rotation cannot be measured for exoplanets.

Host star

HD 180617

Type
M-type (Red Dwarf)
Spectral type
M2.5 V
Temperature
3,534 K
Radius
0.481 ☉
Mass
0.484 ☉
Known planets
1 (this one)
Luminosity
0.0324 ☉

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.

Ice Giant

Magnetic FieldModerate Activity
Why is this a Ice Giant?Your planet has moderate mass (12.2x Earth) with significant water, carbon, and nitrogen content, characteristic of ice giants.
Ice giants like Uranus and Neptune have icy interiors with thick atmospheres of hydrogen and helium, but not enough to be classified as gas giants.
Classification Criteria:
✓ Mass: 12.2x Earth (5-20x range)✓ Water/Carbon/Nitrogen rich composition
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 ScoreExtremely Harsh
30
Contributing Factors
temperature40
Extreme temperature - very difficult 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
geology90
Active geology recycles nutrients and drives carbon cycle
Organic Chemistry80
Core organic elements (CHNO) present
rotation100
Optimal rotation period - balanced day/night cycle, moderate weather, and good heat distribution

Physical Properties

Mass
12.20x Earth (7.29e+25 kg)
Radius
2.30x Earth (14,667 km)
This planet: 2.30× Earth radiusEarth: 1× (baseline)
Surface Gravity
2.30x Earth (22.6 m/s²)
Surface Temperature
217 K (-56 °C / -70 °F)
Rotation Period
24.0 hours/day
This planet: 24 h/dayEarth: 24 h/day

Orbital Environment

Star Type
M-type (Red Dwarf)
Distance from Star
0.34 AU (51.3 million km)
Orbital Period
134 days

Atmosphere

Hydrogen and helium with water, methane, and ammonia ices

Elemental Composition

O - Oxygen
41.2%
H - Hydrogen
17.6%
Si - Silicon
11.8%

Surface Characteristics

Icy mantle surrounding rocky core, with hydrogen-helium atmosphere
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