Star in the constellation Aquarius
4 Aquarii (abbreviated 4 Aqr ) is a binary star system in the constellation Aquarius ,[ 9] located approximately 198 light years away from the Sun.[ 1] 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.[ 2] The system is moving closer to the Earth with a heliocentric radial velocity of −21.5 km/s.[ 5]
This is a visual binary with an orbital period of 200.7 years and an eccentricity of 0.535.[ 7] The magnitude 6.40[ 3] primary, designated component A, is an F-type subgiant star with a stellar classification of F7 IV,[ 4] suggesting that it has exhausted the hydrogen at its core and evolved off the main sequence.[ 7] It has a dynamically-measured mass 1.6[ 7] 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.[ 6] The magnitude 7.43[ 3] secondary, component B, is a suspected F-type main-sequence star of class F6 V.[ 4] The pair are an estimated 1.6 billion years old.[ 8]
References
^ a b c d e f 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 .
^ a b c 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 .
^ a b c 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
^ a b c 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 .
^ a b 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 .
^ a b c 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.
^ a b c d e f 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.
^ a b c 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 .
^ a b "* 4 Aqr" . SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 23 October 2014 .