13point8All planet systems
2 known planets · 181.0 light years

HD 217786

HD 217786 is a yellow star (F8 V) 181.0 light years away, with 2 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

HD 217786

Type
F8 V
Surface
≈ 5,966 K
Size
1.27 × the Sun
Mass
1.14 × the Sun
Brightness
1.89 × the Sun
Habitable zone
1.02–2.39 AU

The planets

HD 217786

HD 217786 c

Year
2.52 days
Distance from star
0.038 AU
Mass
at least 7.3 Earths
Size
2.6 × Earth
Temperature
≈ 1663 K (+1390 °C)
Found
2022, radial velocity (Multiple Observatories)
Too hot
HD 217786

HD 217786 b

Year
3.6 years
Distance from star
2.45 AU
Mass
14 Jupiters
Size
12 × Earth
Temperature
≈ 207 K (-66 °C)
Found
2011, radial velocity (La Silla Observatory)
Near the edge of the habitable zone

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.

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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