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. Read our privacy policy.
Entering orbit…
Habitability
7/ 100
Uninhabitable
Kepler-1321 b rendered in TerraForge from its measured mass, orbit and star

Kepler-1321 b

Also written Kepler-1321b, Kepler 1321b, Kepler 1321 b

Gas Giant2507 light years awayFound 2016
Mass
21.50 × Earth
Radius
4.92 × Earth
Gravity
0.89 g
Surface (est.)
624 K
Year
11.1 days
From Earth
2,508 ly
Mass
21.50 × Earth
Radius
4.92 × Earth
Gravity
0.89 g
Surface (est.)
624 K
Year
11.1 days
From Earth
2,508 ly

Kepler-1321 system

Type
K-type (Orange)
Temperature
4,094 K
Radius
0.53 ☉
Mass
0.54 ☉
Planets
3
Luminosity
0.137 ☉

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.

Kepler-1321 c0.027 AU6.3 M⊕
Kepler-1321 d0.050 AU7.4 M⊕
Kepler-1321 b0.078 AUYou are here22 M⊕
Habitable zone

Star and planets drawn to scale: the star is 12 times as wide as Kepler-1321 b, so only its edge is in view. Orbits spaced as in the star system view.

Kepler-1321 b, from the NASA Exoplanet Archive (found 2016). Measured: 21.5 Earth masses, 0.0781 AU, a 4094 K K-type star. Composition inferred from a measured bulk density of 0.18x Earth's, larger than even a pure water/ice world of this mass, suggesting a water-rich interior under roughly a 32% hydrogen/helium envelope by mass, with a day locked to its 11.1-day year, as anything orbiting this close would be. Note: TerraForge comes out at 624 K against the archive's 408 K, because it models stars by spectral class, and Kepler-1321 is not an average K-type.

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

Gas Giant
Magnetic FieldExtreme Activity
Kepler-1321 b has 64.5% hydrogen and helium, combined with a mass of 21.5x 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: 64.5% (>60% required)✓ Mass: 21.5x Earth (>10x required)

Reading Kepler-1321 b’s atmosphere

Dominant elements: H, O, He, Si, N, CThis is what a telescope would measure while Kepler-1321 b crosses in front of its star: starlight passes through the atmosphere and spreads into a rainbow band. Each dark line marks a wavelength the atmosphere absorbed.Every element absorbs its own signature wavelengths — hydrogen always darkens the same two spots, calcium another pair, and so on. Astronomers match the lines in a real spectrum against a library of these signatures to say what an atmosphere is made of, light-years away, without ever visiting. A deeper line generally means more of that element is present.Kepler-1321 b sits about 2508 light-years away, found by the transit method. Most catalogued distances trace back to parallax: as Earth orbits the Sun, a nearby star appears to shift very slightly against the distant background stars, and the size of that shift gives its distance directly.
Further reading
ExoplanetsSara Seager (editor)The field's standard reference: how planets are found, how they form, and what their atmospheres are made of.The Planet FactoryElizabeth TaskerHow planets are made, and why so few of them come out like Earth.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.
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
7
Contributing Factors
temperature5
Scorching - hot enough to melt lead, though rock stays solid; no chance for life
atmosphere18

Hydrogen and helium dominated with trace methane and ammonia

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 - days and nights each last several Earth days, bringing extreme temperature swings

Physical Properties

Mass
21.50x Earth (1.28e+26 kg)
Radius
2.78x Earth (17,716 km)
This planet: 2.78× Earth radiusEarth: 1× (baseline)
Surface Gravity
2.78x Earth (27.3 m/s²)
Surface Temperature
624 K (351 °C / 663 °F)
Rotation Period
266.4 hours/day (slower than Earth)
This planet: 266 h/dayEarth: 24 h/day

Elemental Composition

A dark ringed planet hanging over the horizon of a rocky moon, its rings lit by a distant sun

New: Stand on Your Moons 🌒

A planet's surface view isn't the only ground any more. Press the surface button on a planet with moons and it asks where to stand: the planet itself, or any moon still in orbit, each tagged with what it became — ocean, ice, carbon, volcanic. Every moon gets its own ground and sky from its own physics: airless rock under a black sky, ice cracked by geysers over a hidden sea, sulfur plains shaking with eruptions, or orange haze you can't see the sun through. And hanging over the horizon, there's the planet you built.

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. Read our privacy policy.

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
Idea
Bug
Pain point
Other