Kepler-21 is 354 light-years from the Sun. The NASA Exoplanet Archive lists 1 planet around this F6 IV star; the first was found in 2012 by transit (Kepler).
Fly there in 3DKepler-21 b goes round its star every 2.79 days, 32 times as often as Mercury goes round the Sun.
Kepler-21 is one of 2 stars in its system. The position of the other star is not catalogued, so only Kepler-21 and its planets are drawn.
| Spectral type | F6 IV |
| Surface temperature | 6,305 K |
| Mass | 1.408 solar masses |
| Radius | 1.902 solar radii |
| Luminosity | 5.188 times the Sun |
| Apparent magnitude | 8.25 |
| Age | about 2.84 billion years |
| Distance from the Sun | 353.9 light-years (108.5 parsecs) |
| Position (J2000) | RA 287.3620°, Dec 38.7141° |
| Constellation | Lyra |
| Planet | Year | Orbit | Radius | Mass | Found |
|---|---|---|---|---|---|
| Kepler-21 b | 2.79 days | 0.0434 AU | 1.639 R⊕ | 7.5 M⊕ | Transit, 2012 |
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.