Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
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Constellation | Aquarius |
Right ascension | 21 25 16.95755 |
Declination | −03° 33′ 24.2964″ |
Apparent magnitude (V) | 5.48 |
Characteristics | |
Spectral type | K4III |
B−V color index | 1.451±0.011 |
Astrometry | |
Radial velocity (Rv) | −24.5±2 km/s |
Proper motion (μ) | RA: −12.061 mas/yr Dec.: −69.973 mas/yr |
Parallax (π) | 7.8747 ± 0.2182 mas |
Distance | 410 ± 10 ly (127 ± 4 pc) |
Absolute magnitude (MV) | 0.11 |
Details | |
Radius | 28.01+1.09 −2.12 R☉ |
Luminosity | 203.4±6.4 L☉ |
Surface gravity (log g) | 1.79 cgs |
Temperature | 4119+165 −78 K |
Metallicity | −0.08 dex |
Other designations | |
BD−04°5446, FK5 3708, HD 203926, HIP 105767, HR 8199, SAO 145384 | |
Database references | |
SIMBAD | data |
21 Aquarii is a single 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. This object is a member of the HR 1614 moving group, and is moving closer to the Earth with a heliocentric radial velocity of −24.5 km/s.
This object is an evolved giant star with a stellar classification of K4 III. As a result of having exhausted the hydrogen at its core, it has expanded to 27 times the radius of the Sun. The star is radiating 203 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,120 K.
References
- ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
- ^ Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey. 5. Bibcode:1999MSS...C05....0H.
- ^ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Carnegie Institute Washington D.C. Publication. Bibcode:1953GCRV..C......0W.
- ^ McWilliam, Andrew (December 1990). "High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances". Astrophysical Journal Supplement Series. 74: 1075–1128. Bibcode:1990ApJS...74.1075M. doi:10.1086/191527.
- Eggleton, P. P.; Tokovinin, A. A. (2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
- Eggen, Olin J.; Iben, Icko Jr. (April 1991), "First giant branch and asymptotic giant branch stars in nearby aggregates", Astronomical Journal, 101: 1377–1407, Bibcode:1991AJ....101.1377E, doi:10.1086/115773.
Constellation of Aquarius | |||||||||||||
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