Star · G3 V
WASP-21
WASP-21 is a main-sequence star of spectral type G3 V in the constellation Pegasus, 842.9 light-years from the Sun. It is orbited by 1 confirmed exoplanet(s).
| Constellation | Pegasus |
|---|---|
| Distance | 842.9 light-years (258.4 pc) |
| Apparent magnitude | magnitude 11.59 |
| Absolute magnitude | magnitude 4.53 |
| Spectral type | G3 V |
| Surface temperature | 5,800 K |
| Luminosity | 2.01 L☉ |
| Radius | 1.06 R☉ |
| Mass | 1.01 M☉ |
| Age | 12.0 billion years |
| Metallicity [Fe/H] | -0.22 |
| Right ascension (J2000) | 23h 09m 58.3s |
| Declination (J2000) | +18° 23′ 46″ |
| Space velocity (relative to the Sun) | 31.6 km/s |
In the sky
A telescope is needed to see it: its apparent magnitude is 11.59. Visible from the whole Northern Hemisphere and south to latitude 72° S. North of latitude 72° N it never sets. It stands highest at midnight in September, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out around the year 1183. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 15 million years.
The Sun seen from there
From a planet around WASP-21, the Sun would look like a star of magnitude 11.89, in the direction where our sky has the constellation Crater. It would be invisible to the naked eye.
Planets
- WASP-21 b 4.32-day orbit · 12 R⊕
Stellar parameters from the NASA Exoplanet Archive; position and brightness from the HYG / AT-HYG catalogue.