4 Aquarii

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4 Aquarii
Observation data
Epoch J2000       Equinox J2000
Constellation Aquarius
Right ascension 20 h 51 m 25.74827 s [1]
Declination ?05° 37′ 35.8719″ [1]
Apparent magnitude  (V) 5.99 [2] (6.40 + 7.43) [3]
Characteristics
Spectral type F7 IV + F6: V: [4]
B?V color index 0.464 ± 0.003 [2]
Astrometry
Radial velocity (R v ) ?21.50 [5]  km/s
Proper motion (μ) RA:  95.47 [1]   mas / yr
Dec.:  1.78 [1]   mas / yr
Parallax (π) 16.47 ± 0.59  mas [1]
Distance 198 ± 7  ly
(61 ± 2  pc )
Absolute magnitude  (M V ) 2.15 [6]
Orbit [7]
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 [6]
4 Aqr A
Mass 1.618 ± 0.004 [7]   M ☉
Luminosity 11.0  L ☉
Surface gravity (log  g ) 3.79  cgs
Temperature 6,440  K
Metallicity [Fe/H] 0.18 [8]   dex
Rotational velocity ( v  sin  i ) 34.6 km/s
Age 1.60 [8]   Gyr
4 Aqr B
Mass 1.331 ± 0.003 [7]   M ☉
Other designations
4 Aqr , BD ?06°5604 , HD  198571, HIP  102945, HR  7982, SAO  144877, WDS J2051.4-0538 [9]
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 , [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 [ edit ]

  1. ^ 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 .
  2. ^ 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 .
  3. ^ 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
  4. ^ 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 .
  5. ^ 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 .
  6. ^ 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.
  7. ^ 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.
  8. ^ 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 .
  9. ^ a b "* 4 Aqr" . SIMBAD . Centre de donnees astronomiques de Strasbourg . Retrieved 23 October 2014 .
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