53 Aquarii

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53 Aquarii
Diagram showing star positions and boundaries of the Aquarius constellation and its surroundings
Cercle rouge 100%.svg

Location of 53 Aquarii (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
Right ascension 22h 26m 34.2753s[1]
Declination –16° 44′ 31.697″[1]
Apparent magnitude (V) 5.56[2] (6.35/6.57)[3]
Spectral type G1 V + G5 V Fe–0.8 CH–1[4]
U−B color index +0.09[2]
B−V color index +0.61[2]
Radial velocity (Rv) +2.1[5] km/s
Proper motion (μ) RA: +200.59[1] mas/yr
Dec.: +14.51[1] mas/yr
Parallax (π) 49.50 ± 1.23[1] mas
Distance 66 ± 2 ly
(20.2 ± 0.5 pc)
Absolute magnitude (MV) 4.05[5] (4.94/4.87)[3]
Primary 53 Aqr A
Companion 53 Aqr B
Period (P) 3500 yr
Semi-major axis (a) 14.88″
Eccentricity (e) 0.90
Inclination (i) 44.13°
Longitude of the node (Ω) 294.55°
Periastron epoch (T) B 2023
Argument of periastron (ω)
53 Aqr A
Mass 1.01[7] M
Radius 1.11[8] R
Luminosity 1.39[8] L
Surface gravity (log g) 4.46[3] cgs
Temperature 5,922[3] K
Metallicity [Fe/H] –0.10[3] dex
Rotational velocity (v sin i) 8[9] km/s
Age 0.18–0.37[10] Gyr
53 Aqr B
Mass 0.99[7] M
Surface gravity (log g) 4.44[3] cgs
Temperature 5,811[3] K
Metallicity [Fe/H] –0.19[3] dex
Rotational velocity (v sin i) 9[9] km/s
Other designations
GJ 859, HIP 110778.[11]
53 Aqr A: BD–17 6521, HD 212698, HR 8545, LTT 9026, SAO 165078.
53 Aqr B: BD–17 6520, HD 212697, HR 8544, LTT 9025, SAO 165077.
Database references
53 Aqr A
53 Aqr B

53 Aquarii (abbreviated 53 Aqr) is a binary star[12] system in the equatorial constellation of Aquarius. 53 Aquarii is its Flamsteed designation though the star also bears the Bayer designation of f Aquarii. The combined apparent visual magnitude of the pair is a 5.56,[2] making it just visible to the naked eye in dark suburban skies. Based upon an annual parallax shift of 49.50 milliarcseconds for the first component, this system is located at a distance of approximately 65 light-years (20 parsecs) from Earth.[1]

This is a wide binary star system with a projected separation of 100 astronomical units; indicating that the two stars are at least this distance apart.[8] The primary component is a solar-type main sequence star with a stellar classification of G1 V.[4] It has about 99% of the Sun's mass, 111% of the Sun's radius, and shines with 139% of the luminosity of the Sun.[8] This energy is being emitted from an outer envelope at an effective temperature of 5,922 K,[3] giving it the golden hue of a G-type star.[13] An examination of the primary component with the Spitzer space telescope failed to detect any infrared excess that might otherwise be an indication of a circumstellar debris disk.[8]

The companion is a slightly cooler star with an effective temperature of 5,811 K.[3] It has a stellar classification of G5 V Fe–0.8 CH–1,[4] indicating it is a chemically peculiar G-type main sequence star showing an under-abundance of iron and the molecule CH in its spectrum. As of 2008, it has an angular separation of 1.325 arcseconds along a position angle of 30.9° from the primary.[14]

This system is coeval with the Castor Moving Group of stars that share a common motion through space; hence it is a candidate member of that association. This suggests that the system is young; its estimated age is in the range of 180 to 370 million years, based upon the spectrum and X-ray luminosity, respectively.[10]


  1. ^ a b c d e f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, Bibcode:2007A&A...474..653V, arXiv:0708.1752Freely accessible, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d Nicolet, B. (1978), "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System", Astronomy and Astrophysics Supplement Series, 34: 1–49, Bibcode:1978A&AS...34....1N. 
  3. ^ a b c d e f g h i j Pasquini, L.; Liu, Q.; Pallavicini, R. (July 1994), "Lithium abundances of nearby solar-like stars", Astronomy and Astrophysics, 287 (1): 191–205, Bibcode:1994A&A...287..191P. 
  4. ^ a b c Gray, R. O.; et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Northern Sample I", The Astronomical Journal, 132 (1): 161–170, Bibcode:2006AJ....132..161G, arXiv:astro-ph/0603770Freely accessible, doi:10.1086/504637. 
  5. ^ a b Nordström, B.; et al. (May 2004), "The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ˜14 000 F and G dwarfs", Astronomy and Astrophysics, 418: 989–1019, Bibcode:2004A&A...418..989N, arXiv:astro-ph/0405198Freely accessible, doi:10.1051/0004-6361:20035959. 
  6. ^ "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory. Retrieved 3 June 2017. 
  7. ^ a b Cvetkovic, Z.; Ninkovic, S. (2010). "On the Component Masses of Visual Binaries". Serbian Astronomical Journal. 180: 71–80. Bibcode:2010SerAJ.180...71C. doi:10.2298/SAJ1080071C. 
  8. ^ a b c d e Plavchan, Peter; et al. (June 2009), "New Debris Disks Around Young, Low-Mass Stars Discovered with the Spitzer Space Telescope", The Astrophysical Journal, 698 (2): 1068–1094, Bibcode:2009ApJ...698.1068P, arXiv:0904.0819Freely accessible, doi:10.1088/0004-637X/698/2/1068. 
  9. ^ a b Torres, C. A. O.; et al. (December 2006), "Search for associations containing young stars (SACY). I. Sample and searching method", Astronomy and Astrophysics, 460 (3): 695–708, Bibcode:2006A&A...460..695T, arXiv:astro-ph/0609258Freely accessible, doi:10.1051/0004-6361:20065602. 
  10. ^ a b Maldonado, J.; et al. (October 2010), "A spectroscopy study of nearby late-type stars, possible members of stellar kinematic groups", Astronomy and Astrophysics, 521: A12, Bibcode:2010A&A...521A..12M, arXiv:1007.1132Freely accessible, doi:10.1051/0004-6361/201014948. 
  11. ^ "53 Aqr -- Double or multiple star", SIMBAD Astronomical Object Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-07-14.  See also the children entries.
  12. ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. Bibcode:2008MNRAS.389..869E. arXiv:0806.2878Freely accessible. doi:10.1111/j.1365-2966.2008.13596.x. 
  13. ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on March 10, 2012, retrieved 2012-01-16. 
  14. ^ Tokovinin, A.; Cantarutti, R. (February 2008), "First Speckle Interferometry at SOAR Telescope with Electron-Multiplication CCD", Publications of the Astronomical Society of the Pacific, 120 (864): 170–177, Bibcode:2008PASP..120..170T, doi:10.1086/528809.