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Entering orbit…
Habitability
32/ 100
Extremely Harsh
KOI-351 h rendered in TerraForge from its measured mass, orbit and star

KOI-351 h

Also written KOI-351h, KOI 351h, KOI 351 h

Gas Giant2764 light years awayFound 2013
Mass
203.00 × Earth
Radius
11.30 × Earth
Gravity
1.59 g
Surface (est.)
330 K
Year
332 days
From Earth
2,766 ly
Mass
203.00 × Earth
Radius
11.30 × Earth
Gravity
1.59 g
Surface (est.)
330 K
Year
332 days
From Earth
2,766 ly

KOI-351 system

Type
F-type (White)
Temperature
6,031 K
Radius
1.19 ☉
Mass
1.24 ☉
Planets
8
Luminosity
1.86 ☉

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.

KOI-351 b0.074 AU2.3 M⊕
KOI-351 c0.089 AU1.8 M⊕
Kepler-90 i0.12 AU2.3 M⊕
KOI-351 d0.32 AU8.6 M⊕
KOI-351 e0.42 AU7.6 M⊕
KOI-351 f0.48 AU8.7 M⊕
KOI-351 g0.72 AU15 M⊕
KOI-351 h0.97 AUYou are here203 M⊕
Habitable zone

Star and planets drawn to scale: the star is 11 times as wide as KOI-351 h, so only its edge is in view. Orbits spaced as in the star system view.

KOI-351 h, also known as Kepler-90 h, is the outermost and largest known planet of Kepler-90, a Sun-like star about 2,800 light-years away with eight planets, as many as our solar system. It is a gas giant about 11 times Earth's width, a little larger than Jupiter, and it orbits every 332 days at about the same distance from its star as Earth is from the Sun.

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

Gas Giant
Life unlikely — no phosphorus — DNA and ATP are built on itMagnetic FieldExtreme Activity
KOI-351 h has 86.0% hydrogen and helium, combined with a mass of 203.0x 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: 203.0x Earth (>10x required)

Reading KOI-351 h’s atmosphere

Dominant elements: H, He, O, C, NThis is what a telescope would measure while KOI-351 h 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.KOI-351 h sits about 2766 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 ScoreExtremely Harsh
32
Contributing Factors
temperature59
Warm - livable, but heat stress grows with every degree
atmosphere30

Hydrogen and helium dominated with trace methane and ammonia

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 Chemistry80
Core organic elements (CHNO) present
rotation100
Optimal rotation period - balanced day/night cycle, moderate weather, and good heat distribution

Physical Properties

Mass
203.00x Earth (1.21e+27 kg)
Radius
5.88x Earth (37,443 km)
This planet: 5.88× Earth radiusEarth: 1× (baseline)
Surface Gravity
5.88x Earth (57.7 m/s²)
Surface Temperature
330 K (57 °C / 135 °F)
Rotation Period
24.0 hours/day
This planet: 24 h/dayEarth: 24 h/day

Elemental Composition

How TerraForge built this world

KOI-351 h, from the NASA Exoplanet Archive (found 2013). Measured: 203 Earth masses, 0.971 AU, a 6031 K F-type star. Composition inferred from a mass of 203 Earths, which is giant territory whatever its 0.14x density suggests, with an assumed 24-hour day — rotation cannot be measured for exoplanets.

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.

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