| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 20 51 25.74827 |
| Declination | −05° 37′ 35.8719″ |
| Apparent magnitude (V) | 5.99 (6.40 + 7.43) |
| Characteristics | |
| Spectral type | F7 IV + F6: V: |
| B−V color index | 0.464±0.003 |
| Astrometry | |
| Radial velocity (Rv) | −21.50 km/s |
| Proper motion (μ) | RA: 95.47 mas/yr Dec.: 1.78 mas/yr |
| Parallax (π) | 16.47 ± 0.59 mas |
| Distance | 198 ± 7 ly (61 ± 2 pc) |
| Absolute magnitude (MV) | 2.15 |
| Orbit | |
| Period (P) | 200.7±1.1 yr |
| Semi-major axis (a) | 0.816±0.006″ |
| Eccentricity (e) | 0.535+0.006 −0.005 |
| Inclination (i) | 64.06+0.26 −0.27° |
| Longitude of the node (Ω) | 174.31+0.38 −0.39° |
| Periastron epoch (T) | B 1,896.8+0.39 −0.40 |
| Argument of periastron (ω) (secondary) | 45.9±1.2° |
| Details | |
| 4 Aqr A | |
| Mass | 1.618±0.004 M☉ |
| Luminosity | 11.0 L☉ |
| Surface gravity (log g) | 3.79 cgs |
| Temperature | 6,440 K |
| Metallicity | 0.18 dex |
| Rotational velocity (v sin i) | 34.6 km/s |
| Age | 1.60 Gyr |
| 4 Aqr B | |
| Mass | 1.331±0.003 M☉ |
| Other designations | |
| 4 Aqr, BD−06°5604, HD 198571, HIP 102945, HR 7982, SAO 144877, WDS J2051.4-0538 | |
| Database references | |
| SIMBAD | 4 Aqr |
| 4 Aqr A | |
| 4 Aqr B | |
4 Aquarii (abbreviated 4 Aqr) is a binary star system in the constellation Aquarius, located approximately 198 light years away from the Sun. 4 Aquarii is the Flamsteed designation. It is visible to the naked eye as a dim, yellow-white hued star with a combined apparent visual magnitude of 5.99. The system is moving closer to the Earth with a heliocentric radial velocity of −21.5 km/s.
This is a visual binary with an orbital period of 200.7 years and an eccentricity of 0.535. The magnitude 6.40 primary, designated component A, is an F-type subgiant star with a stellar classification of F7 IV, suggesting that it has exhausted the hydrogen at its core and evolved off the main sequence. It has a dynamically-measured mass 1.6 times that of the Sun and is radiating 11 times the Sun's luminosity from its photosphere at an effective temperature of 6,440 K. The magnitude 7.43 secondary, component B, is a suspected F-type main-sequence star of class F6 V. The pair are an estimated 1.6 billion years old.
References
- ^ van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
- ^ 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.
- ^ Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466, Bibcode:2001AJ....122.3466M, doi:10.1086/323920
- ^ Corbally, C. J.; Garrison, R. F. (August 1980). "New spectral classifications on the MK system for visual double stars". Publications of the Astronomical Society of the Pacific. 92: 493–496. Bibcode:1980PASP...92..493C. doi:10.1086/130700. S2CID 121017167.
- ^ Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
- ^ Luck, R. Earle (January 2017). "Abundances in the Local Region II: F, G, and K Dwarfs and Subgiants". The Astronomical Journal. 153 (1): 19. arXiv:1611.02897. Bibcode:2017AJ....153...21L. doi:10.3847/1538-3881/153/1/21. S2CID 119511744. 21.
- ^ Mendez, Rene A.; et al. (November 2017). "Orbits for 18 Visual Binaries and Two Double-line Spectroscopic Binaries Observed with HRCAM on the CTIO SOAR 4 m Telescope, Using a New Bayesian Orbit Code Based on Markov Chain Monte Carlo". The Astronomical Journal. 154 (5): 22. arXiv:1709.06582. Bibcode:2017AJ....154..187M. doi:10.3847/1538-3881/aa8d6f. S2CID 55695873. 187.
- ^ 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. S2CID 56118016.
- ^ "* 4 Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 23 October 2014.
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