20 Aquarii
Star in the constellation Aquarius
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20 Aquarii, abbreviated 20 Aqr, is a star in the constellation Aquarius. 20 Aquarii is the Flamsteed designation. It is a dim star with an apparent visual magnitude of 6.38.[2] Based upon an annual parallax shift of 15.34 mas,[1] it is located 213 light years away but is moving closer to the Earth with a heliocentric radial velocity of −23 km/s.[5] The star is predicted to come to within 110 light-years in around 1.9 million years.[2]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 21h 24m 51.67515s[1] |
| Declination | −03° 23′ 54.0858″[1] |
| Apparent magnitude (V) | 6.38[2] |
| Characteristics | |
| Spectral type | F0 V[3] or F0 III[4] |
| B−V color index | 0.334±0.002[2] |
| Astrometry | |
| Radial velocity (Rv) | −23.2±2.9[5] km/s |
| Proper motion (μ) | RA: −6.125[1] mas/yr Dec.: −49.515[1] mas/yr |
| Parallax (π) | 15.3426±0.0730 mas[1] |
| Distance | 213 ± 1 ly (65.2 ± 0.3 pc) |
| Absolute magnitude (MV) | 2.37[2] |
| Details | |
| Mass | 1.52[6] M☉ |
| Luminosity | 9.38[2] L☉ |
| Surface gravity (log g) | 4.17[6] cgs |
| Temperature | 7,314±249[6] K |
| Rotational velocity (v sin i) | 92[7] km/s |
| Age | 761[6] Myr |
| Other designations | |
| 20 Aqr, BD−05°5444, GC 29976, HD 203843, HIP 105729, HR 8192, SAO 145376[8] | |
| Database references | |
| SIMBAD | data |
This is an F-type main-sequence star with a stellar classification of F0 V.[3] (Cowley and Fraquelli [1974] had given it a class of F0 III.)[4] It is a suspected[9] chemically peculiar Am star showing metallic lines.[10] It is 761[6] million years old with a high projected rotational velocity of 92 km/s.[7] The star has 1.52[6] times the mass of the Sun and is radiating 9[2] times the Sun's luminosity from its photosphere at an effective temperature of about 7,314 K.[6]