53 Aquarii

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]

53 Aquarii
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]
Characteristics
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]
Astrometry
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
Distance66 ± 2 ly
(20.2 ± 0.5 pc)
Absolute magnitude (MV)4.05[5] (4.94/4.87)[3]
Orbit[6]
Primary53 Aqr A
Companion53 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)
(secondary)		151.40°
Details
53 Aqr A
Mass1.01[7] M☉
Radius1.11[8] R☉
Luminosity1.39[8] L☉
Surface gravity (log g)4.46[3] cgs
Temperature5,922[3] K
Metallicity [Fe/H]–0.10[3] dex
Rotational velocity (v sin i)8[9] km/s
Age0.18–0.37[10] Gyr
53 Aqr B
Mass0.99[7] M☉
Surface gravity (log g)4.44[3] cgs
Temperature5,811[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
SIMBAD53 Aqr
53 Aqr A
53 Aqr B

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]

References
  1. van Leeuwen, F. (November 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.
  2. 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. 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. 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, arXiv:astro-ph/0603770, Bibcode:2006AJ....132..161G, doi:10.1086/504637.
  5. 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, arXiv:astro-ph/0405198, Bibcode:2004A&A...418..989N, doi:10.1051/0004-6361:20035959.
  6. "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory. Retrieved 3 June 2017.
  7. 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. 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, arXiv:0904.0819, Bibcode:2009ApJ...698.1068P, doi:10.1088/0004-637X/698/2/1068.
  9. 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, arXiv:astro-ph/0609258, Bibcode:2006A&A...460..695T, doi:10.1051/0004-6361:20065602.
  10. 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, arXiv:1007.1132, Bibcode:2010A&A...521A..12M, doi:10.1051/0004-6361/201014948.
  11. "53 Aqr". SIMBAD. 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. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. 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.
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