24 Aquarii
24 Aquarii is a triple star[6] system in the equatorial constellation of Aquarius. 24 Aquarii is the Flamsteed designation. The apparent magnitude of this system is 6.66,[2] which, according to the Bortle Dark-Sky Scale, means it is a faint star that is just visible to the naked eye from dark, rural skies. It has an annual parallax shift of 25.08 mas,[1] which is equivalent to a distance of 130 light-years (40 parsecs) from Earth. The system is moving closer to the Earth with a heliocentric radial velocity of −16 km/s.[2]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 21h 39m 31.53468s[1] |
| Declination | −00° 03′ 04.1095″[1] |
| Apparent magnitude (V) | 6.66[2] |
| Characteristics | |
| Spectral type | F7 III[3] OR F7V + ? + F9V[4] |
| B−V color index | +0.52[5] |
| Astrometry | |
| Radial velocity (Rv) | −15.86±0.06[2] km/s |
| Proper motion (μ) | RA: +215.367[1] mas/yr Dec.: +17.077[1] mas/yr |
| Parallax (π) | 25.0839 ± 0.6277[1] mas |
| Distance | 130 ± 3 ly (39.9 ± 1.0 pc) |
| Absolute magnitude (MV) | 3.45[2] |
| Orbit[6] | |
| Period (P) | 48.65 yr |
| Semi-major axis (a) | 0.448″ |
| Eccentricity (e) | 0.868 |
| Inclination (i) | 58.0° |
| Longitude of the node (Ω) | 139.3° |
| Periastron epoch (T) | 1971.55 |
| Argument of periastron (ω) (secondary) | 293.0° |
| Details[7] | |
| 24 Aqr Aa | |
| Mass | 1.25 M☉ |
| Radius | 1.42+0.05 −0.08[1] R☉ |
| Luminosity | 2.864±0.080[1] L☉ |
| Temperature | 6,231 K |
| Metallicity [Fe/H] | –0.09 dex |
| Age | 3.5 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
The calculated orbit of the visual binary has a period of 48.65 years and a large eccentricity of 0.868.[6] The primary, component A, is itself a single-lined spectroscopic binary with a period of 5.8839 days and an eccentricity of 0.071±0.006.[4] One study gives the system a stellar classification of F7 III,[3] suggesting it contains an evolved giant star. Other classifications give classes matching F-type main-sequence stars for components Aa and B.[4]
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.
- Fehrenbach, C. (1966), "La mesure des vitesses radiales au prisme objectif XIX. Liste de 893 vitesses radiales determinees au prisme objectif a vision directe", Publications de l'Observatoire de Haute-Provence, 8: 25, Bibcode:1966POHP....8...25F.
- Griffin, R. F.; et al. (June 1996), "Spectroscopic binary orbits from photoelectric radial velocities. Paper 128: 24 Aquarii", The Observatory, 116: 162–175, Bibcode:1996Obs...116..162G.
- Cousins, A. W. J.; Stoy, R. H. (1962), "Photoelectric magnitudes and colours of Southern stars", Royal Observatory Bulletin, 64: 103, Bibcode:1962RGOB...64..103C.
- Branham, Richard L., Jr. (March 2005), "Calculating the Apparent Orbit of a Double Star", The Astrophysical Journal, 622 (1): 613–61, Bibcode:2005ApJ...622..613B, doi:10.1086/427870.
- Casagrande, L.; et al. (June 2011), "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey", Astronomy and Astrophysics, 530: A138, arXiv:1103.4651, Bibcode:2011A&A...530A.138C, doi:10.1051/0004-6361/201016276.
