Observation data Epoch J2000.0 Equinox J2000.0 ( ICRS) | |
---|---|
Constellation | Aquarius |
Right ascension | 21h 25m 16.95755s [1] |
Declination | −03° 33′ 24.2964″ [1] |
Apparent magnitude (V) | 5.48 [2] |
Characteristics | |
Spectral type | K4III [3] |
B−V color index | 1.451±0.011 [2] |
Astrometry | |
Radial velocity (Rv) | −24.5±2 [4] km/s |
Proper motion (μ) |
RA: −12.061
[1]
mas/
yr Dec.: −69.973 [1] mas/ yr |
Parallax (π) | 7.8747 ± 0.2182 mas [1] |
Distance | 410 ± 10
ly (127 ± 4 pc) |
Absolute magnitude (MV) | 0.11 [2] |
Details | |
Radius | 28.01+1.09 −2.12 [1] R☉ |
Luminosity | 203.4±6.4 [1] L☉ |
Surface gravity (log g) | 1.79 [5] cgs |
Temperature | 4119+165 −78 [1] K |
Metallicity [Fe/H] | −0.08 [5] dex |
Other designations | |
Database references | |
SIMBAD | data |
21 Aquarii is a single [6] star in the zodiac constellation of Aquarius. 21 Aquarii is the Flamsteed designation. It is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of 5.49. [2] This object is a member of the HR 1614 moving group, [7] and is moving closer to the Earth with a heliocentric radial velocity of −24.5 km/s. [4]
This object is an evolved giant star with a stellar classification of K4 III. [3] As a result of having exhausted the hydrogen at its core, it has expanded to 27 [1] times the radius of the Sun. The star is radiating 203 [1] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,120 K. [1]