WASP-21
WASP-21 is a G-type star (spectral type G3V) that is reaching the end of its main sequence lifetime approximately 850 light years from Earth in the constellation of Pegasus. The star is relatively metal-poor, having 40% of heavy elements compared to the Sun. Kinematically, WASP-21 belongs to the thick disk of the Milky Way. It has an exoplanet named WASP-21b.
Size comparison between Sun and WASP-21 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Pegasus |
| Right ascension | 23h 09m 58.25s |
| Declination | +18° 23′ 45.9″ |
| Apparent magnitude (V) | 11.58 ± 0.08 |
| Characteristics | |
| Spectral type | G3V |
| Astrometry | |
| Radial velocity (Rv) | -89.45 km/s |
| Proper motion (μ) | RA: 17.597 ± 0.074 mas/yr Dec.: 18.867 ± 0.05 mas/yr |
| Parallax (π) | 3.8412 ± 0.0427 mas |
| Distance | 849 ± 9 ly (260 ± 3 pc) |
| Absolute magnitude (MV) | 4.97 |
| Details | |
| Mass | 0.89 ± 0.071 M☉ |
| Radius | 1.136 ± 0.049 R☉ |
| Surface gravity (log g) | 4.277 ± 0.025 cgs |
| Temperature | 5800 ± 100 K |
| Metallicity | -0.4 ± 0.1 |
| Metallicity [Fe/H] | -0.46 ± 0.11 dex |
| Rotational velocity (v sin i) | 1.5 ± 0.6 km/s |
| Age | 12 ± 5 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
The survey in 2012 have failed to find any stellar companions to WASP-21.
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