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6 known planets · 921.6 light years

Kepler-20

Kepler-20 is a yellow star 921.6 light years away, with 6 confirmed planets. Distances and orbital speeds are to scale; the star and planets are enlarged so you can see them.

Day 0
habitable zone (estimate)planet orbits

Green band: where liquid water could exist on a planet's surface. Drag to turn the system, pinch or scroll to zoom.

The star

The star

Kepler-20

Type
yellow star
Surface
≈ 5,495 K
Size
0.96 × the Sun
Mass
0.95 × the Sun
Brightness
0.685 × the Sun
Habitable zone
0.631–1.5 AU

The planets

Kepler-20

Kepler-20 b

Year
3.70 days
Distance from star
0.0457 AU
Mass
9.7 Earths
Size
1.8 × Earth
Temperature
≈ 1187 K (+914 °C)
Found
2011, transit (Kepler)
Too hot
Kepler-20

Kepler-20 e

Year
6.10 days
Distance from star
0.0637 AU
Mass
0.76 Earths
Size
0.82 × Earth
Temperature
≈ 1004 K (+731 °C)
Found
2011, transit (Kepler)
Too hot
Kepler-20

Kepler-20 c

Year
10.85 days
Distance from star
0.0936 AU
Mass
11 Earths
Size
2.9 × Earth
Temperature
≈ 828 K (+555 °C)
Found
2011, transit (Kepler)
Too hot
Kepler-20

Kepler-20 f

Year
19.58 days
Distance from star
0.139 AU
Mass
1.4 Earths
Size
0.95 × Earth
Temperature
≈ 681 K (+408 °C)
Found
2011, transit (Kepler)
Too hot
Kepler-20

Kepler-20 g

Year
34.94 days
Distance from star
0.205 AU
Mass
at least 20 Earths
Size
4.7 × Earth
Temperature
≈ 524 K (+251 °C)
Found
2016, radial velocity (Multiple Observatories)
Too hot
Kepler-20

Kepler-20 d

Year
77.61 days
Distance from star
0.347 AU
Mass
13 Earths
Size
2.6 × Earth
Temperature
≈ 430 K (+157 °C)
Found
2011, transit (Kepler)
Too hot

Masses found by the wobble method are minimums, because the orbit's tilt is unknown. Temperatures are equilibrium estimates for a bare planet, before any atmosphere.

How we know

The wobble

The planet tugs its star back and forth. Spectrographs measure the tiny shift in the star's light, which gives the planet's year and a minimum mass.

The shadow

The planet passes in front of its star and dims it by a fraction of a percent, every orbit. The dip gives the planet's size and year.

Sources

  1. Planet and star parameters: NASA Exoplanet Archive, Planetary Systems Composite Parameters, retrieved 1 Nov 2026. This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with NASA under the Exoplanet Exploration Program.
  2. Position: HYG Database v4.1 (CC BY-SA 4.0).
  3. Habitable zone: a simple estimate from the star's brightness (√L × 0.95 to 1.67 AU), shown as a guide.
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