Kepler-391 is 2,835 light-years from the Sun. The NASA Exoplanet Archive lists 2 planets around this K2 III-IV star; the first was found in 2014 by transit (Kepler).
Fly there in 3DKepler-391 b goes round its star every 7.42 days, 12 times as often as Mercury goes round the Sun.
| Spectral type | K2 III-IV |
| Surface temperature | 5,038 K |
| Mass | 1.27 solar masses |
| Radius | 2.879 solar radii |
| Luminosity | 4.6 times the Sun |
| Apparent magnitude | 13.177 |
| Age | about 4.365 billion years |
| Distance from the Sun | 2835.1 light-years (869.2 parsecs) |
| Position (J2000) | RA 290.6219°, Dec 51.0573° |
| Constellation | Cygnus |
| Planet | Year | Orbit | Radius | Mass | Found |
|---|---|---|---|---|---|
| Kepler-391 b | 7.42 days | 0.0830 AU | 2.5 R⊕ | 1100 M⊕ | Transit, 2014 |
| Kepler-391 c | 20.5 days | 0.164 AU | 2.88 R⊕ | 450 M⊕ | Transit, 2014 |
Values are the NASA Exoplanet Archive’s composite parameters. A radius marked estimated comes from a mass–radius relation; a mass marked minimum is M sin i. Planet sizes and colours in the 3D view are renderings: none of these worlds has been photographed as more than a point of light.
For a star of 5,038 K, 4.6 times as bright as the Sun, the habitable zone, where starlight could keep water liquid on a rocky surface, runs from about 2.12 to 3.84 AU. None of its known planets orbits inside it. The zone says how much starlight arrives, not whether a planet has water or air. The edges follow Kopparapu et al. (2014), as the 3D view draws them.
The light you see left 2,835 years ago, around 800 BC.