Kepler-186
Where is Kepler-186?
Look southwest, about 82° up at 20:20 in Cygnus.
- Rises
- Always up
- Highest
- 19:58
- Sets
- Never
- Best after dark
- 20:20 · 82°
Can I see Kepler-186?
No. The planets of Kepler-186 can’t be seen with the eye, binoculars or any amateur telescope: they are lost in their star’s light. What you can do is point toward the star.
From London tonight, the star Kepler-186 is above the horizon all night. It’s highest soon after dark, around 20:20, in the southwest at 82°.
Why is Kepler-186 interesting?
Kepler-186 has 5 known planets, discovered in 2014 by the primary transit method.
All of them are close to Earth’s size or mass, based on the catalog values.
What can you see?
Eyes
Direction onlyNot visible.
Binoculars
Not visible.
Telescope
The star is around magnitude 15, a target for large amateur telescopes with a detailed chart. The planets themselves can’t be seen with any backyard telescope.
About
Kepler-186 is a red dwarf star about 560 light-years away in Cygnus, with five known planets. In 2014, Kepler-186f became the first Earth-sized planet found in its star’s habitable zone, where liquid water might exist on the surface.
Kepler-186f is only slightly larger than Earth and orbits every 130 days. Its star is cooler and redder than the Sun, so the planet receives less energy than Earth does.
The planets were discovered by NASA’s Kepler space telescope, which watched the same patch of sky between Cygnus and Lyra for years.
Kepler-186f is only about 10% larger than Earth and sits near the outer edge of its star’s habitable zone. The star is about half the Sun’s size and mass.
Kepler watched for the tiny, regular dips in starlight caused by planets passing in front of their stars. Between 2009 and 2018 it found thousands of planets this way.
The Kepler-186 system
| Planet | Mass | Radius | Orbit | From star | Found | Method |
|---|---|---|---|---|---|---|
| Kepler-186 b | — | 1.06 R⊕ | 3.89 days | 0.0343 AU | 2014 | Primary Transit |
| Kepler-186 c | — | 1.26 R⊕ | 7.27 days | 0.0451 AU | 2014 | Primary Transit |
| Kepler-186 d | — | 1.40 R⊕ | 13.3 days | 0.0781 AU | 2014 | Primary Transit |
| Kepler-186 e | — | 1.27 R⊕ | 22.4 days | 0.11 AU | 2014 | Primary Transit |
| Kepler-186 f | — | 1.17 R⊕ | 129.9 days | 0.432 AU | 2014 | Primary Transit |
Questions
Can I see Kepler-186f?
Is Kepler-186f like Earth?
Sources: The Extrasolar Planets Encyclopaedia (CC BY 4.0); star chart: Wikidata (CC0). Positions computed for your place and time with astronomy-engine. Data & Licences