WASP-21 is 843 light-years from the Sun. The NASA Exoplanet Archive lists 1 planet around this G3 V star; the first was found in 2010 by transit (SuperWASP).
Fly there in 3DWASP-21 b goes round its star every 4.32 days, 20 times as often as Mercury goes round the Sun.
| Spectral type | G3 V |
| Surface temperature | 5,800 K |
| Mass | 1.01 solar masses |
| Radius | 1.06 solar radii |
| Luminosity | 2.015 times the Sun |
| Apparent magnitude | 11.59 |
| Age | about 12 billion years |
| Distance from the Sun | 842.9 light-years (258.4 parsecs) |
| Position (J2000) | RA 347.4928°, Dec 18.3962° |
| Constellation | Pegasus |
| Planet | Year | Orbit | Radius | Mass | Found |
|---|---|---|---|---|---|
| WASP-21 b | 4.32 days | 0.0520 AU | 11.99 R⊕ | 95.345 M⊕ | Transit, 2010 |
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 5,800 K, 2.0 times as bright as the Sun, the habitable zone, where starlight could keep water liquid on a rocky surface, runs from about 1.35 to 2.37 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 843 years ago, around 1180.