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Planet profiles

KOI-351 e

Barren · 2,764 light-years away · Last reviewed October 14, 2026

KOI-351 e rendered in TerraForge from its measured mass, orbit and star
TerraForge's rendering of KOI-351 e, generated by our physics engine from its measured mass, size, orbit and star. An illustration of what the science suggests, not a photograph.
TerraForge classification
Barren
Host star
KOI-351
Distance
2,764 light-years
Orbit
91.9 days
Mass
7.56 × Earth
Radius
2.66 × Earth
Discovered
2013, transit

Figures from the NASA Exoplanet Archive. The classification is TerraForge’s, from its physics model.

KOI-351 e, also known as Kepler-90 e, is the middle planet of a chain of three in the Kepler-90 system. Kepler-90 is a Sun-like star about 2,800 light-years away with eight known planets. Kepler-90 e orbits every 91.9 days, and the NASA Exoplanet Archive lists its radius as about 2.7 times Earth's.

It was one of four planets announced around the star in 2013 by a team led by Juan Cabrera. Its orbit sits between those of Kepler-90 d at about 60 days and Kepler-90 f at about 125 days, and the three are close to a 2 to 3 to 4 ratio of periods, a near-resonant chain in which neighbouring planets regularly tug on each other. The same paper found much stronger interactions between the two giant planets farther out, Kepler-90 g and h. Later work by a team led by D. E. Shaw in 2025 used those interactions to measure g's and h's masses.

Kepler-90 e's own mass has not been measured; the archive's figure of about 7.6 Earth masses is an estimate from its size. At about 2.7 Earth radii, it is likely a mini-Neptune with a thick envelope of gas. It receives about ten times the light Earth gets from the Sun. Like all of Kepler-90's planets, it orbits within about the distance of Earth from the Sun, which makes the system a compact version of our own, with small planets inside and giants outside.

Sources

  1. The Planetary System to KIC 11442793: A Compact Analogue to the Solar System — arXiv (The Astrophysical Journal)
  2. Updated Masses for the Gas Giants in the Eight-Planet Kepler-90 System Via Transit-Timing Variation and Radial Velocity Observations — arXiv (The Astronomical Journal)
A banded gas giant with four moons in different colors: a yellow sulfur moon, two rust-red rock moons and a blue water moon

New: Choose What Your Moons Are Made Of 🌙

Every moon used to be grey rock, white ice or blue ocean, decided for you. Now each one has a "Made of" choice in the builder's Moons tab — silicate rock, iron, water ice, carbon, sulfur, or nitrogen and methane ice — and the physics decides what that becomes. Put water ice too close to the star and it boils off to bare rock. Put sulfur where a neighbouring moon keeps it tidally flexed and it erupts in Io's yellows. Give a Titan-sized moon nitrogen ice far from the sun and it wraps itself in haze. Hang a water moon about the mass of Earth off a giant planet in the habitable zone and it can hold air and open seas — scored for life on the same scale as a planet, with a day as long as its orbit. A tint slider nudges the colour, but only as far as that material could really go.

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