Star · K2 III-IV
Kepler-391
Kepler-391 is a giant star of spectral type K2 III-IV in the constellation Cygnus, 2,835 light-years from the Sun. It is orbited by 2 confirmed exoplanet(s).
| Constellation | Cygnus |
|---|---|
| Distance | 2,835 light-years (869.2 pc) |
| Apparent magnitude | magnitude 13.18 |
| Absolute magnitude | magnitude 3.48 |
| Spectral type | K2 III-IV |
| Surface temperature | 5,040 K |
| Luminosity | 4.6 L☉ |
| Radius | 2.88 R☉ |
| Mass | 1.27 M☉ |
| Age | 4.4 billion years |
| Metallicity [Fe/H] | 0.04 |
| Right ascension (J2000) | 19h 22m 29.3s |
| Declination (J2000) | +51° 03′ 26″ |
| Space velocity (relative to the Sun) | 52.7 km/s |
In the sky
A telescope is needed to see it: its apparent magnitude is 13.18. Visible from the whole Northern Hemisphere and south to latitude 39° S. North of latitude 39° N it never sets. It stands highest at midnight in July, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out around 810 BC. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 50 million years.
The Sun seen from there
From a planet around Kepler-391, the Sun would look like a star of magnitude 14.53, in the direction where our sky has the constellation Carina. It would be invisible to the naked eye.
Planets
- Kepler-391 b 7.42-day orbit · 2.5 R⊕
- Kepler-391 c 20.5-day orbit · 2.88 R⊕
Stellar parameters from the NASA Exoplanet Archive; position and brightness from the HYG / AT-HYG catalogue.