Star · A8 V
KELT-21
KELT-21 is a main-sequence star of spectral type A8 V in the constellation Cygnus, 1,588 light-years from the Sun. It is orbited by 1 confirmed exoplanet(s).
| Constellation | Cygnus |
|---|---|
| Distance | 1,588 light-years (487.0 pc) |
| Apparent magnitude | magnitude 10.52 |
| Absolute magnitude | magnitude 2.08 |
| Spectral type | A8 V |
| Surface temperature | 7,600 K |
| Luminosity | 8.03 L☉ |
| Radius | 1.64 R☉ |
| Mass | 1.46 M☉ |
| Age | 1.6 billion years |
| Metallicity [Fe/H] | -0.41 |
| Right ascension (J2000) | 20h 19m 12.0s |
| Declination (J2000) | +32° 34′ 52″ |
| Space velocity (relative to the Sun) | 14.8 km/s |
In the sky
A telescope is needed to see it: its apparent magnitude is 10.52. Visible from the whole Northern Hemisphere and south to latitude 57° S. North of latitude 57° 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 the year 438. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 28 million years.
The Sun seen from there
From a planet around KELT-21, the Sun would look like a star of magnitude 13.27, in the direction where our sky has the constellation Puppis. It would be invisible to the naked eye.
Planets
- KELT-21 b 3.61-day orbit · 17.8 R⊕
Stellar parameters from the NASA Exoplanet Archive; position and brightness from the HYG / AT-HYG catalogue.