EZ Aquarii

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EZ Aquarii A/B/C
Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
Right ascension 22h 38m 33.73s[1]
Declination –15° 17′ 57.3″[1]
Apparent magnitude (V) 12.87 (13.33/13.27/14.03)[2]
Characteristics
Spectral type M5 V[2]
U−B color index +1.54
B−V color index +1.96[3]
R−I color index +0.64[citation needed]
Astrometry
Radial velocity (Rv) –59.9[4] km/s
Proper motion (μ) RA: +2314[5] mas/yr
Dec.: +2295[5] mas/yr
Parallax (π) 294.3 ± 3.5[6] mas
Distance 11.1 ± 0.1 ly
(3.40 ± 0.04 pc)
Absolute magnitude (MV) 15.64/15.58/16.34[2]
Details
Mass 0.11/0.11/0.10[2] M
Temperature 2,650[7] K
Orbit[8]
Primary EZ Aquarii AC
Companion EZ Aquarii B
Period (P) 2.2506 ± 0.0033 yr
Semi-major axis (a) 0.346″ ± 0.004"
Eccentricity (e) 0.437 ± 0.007
Inclination (i) 112.4° ± 0.5°
Longitude of the node (Ω) 162.1° ± 0.4°
Periastron epoch (T) 1987.236 ± 0.014
Argument of periastron (ω)
(secondary)
–17.7° ± 1.1°
Other designations
Luyten 789-6, GCTP 5475.00, LHS 68, GJ 866, G 156-031.
Database references
SIMBAD data

EZ Aquarii is a triple star system approximately 11.3 ly (3.5 pc) from the Sun in the constellation Aquarius. It is also known as Luyten 789-6 and Gliese 866 and all three components are M-type red dwarfs. The pair EZ Aquarii AC form a spectroscopic binary with a 3.8-day orbit and a 0.03 AU separation. This pair share an orbit with EZ Aquarii B that has an 823-day period.[9] The A and B components of Luyten 789-6 together emit X-rays.[10]

EZ Aquarii is approaching the Solar System and, in about 32,300 years, will be at its minimal distance of about 8.2 ly (2.5 pc) from the Sun.[11] The ChView simulation shows that currently its nearest neighbouring star is Lacaille 9352 at about 4.1 ly (1.3 pc) from EZ Aquarii.

Distance[edit]

EZ Aquarii distance estimates

Source Parallax, mas Distance, pc Distance, ly Ref.
Woolley et al. (1970) 305 ± 9 3.28+0.1
−0.09
10.69+0.33
−0.31
[12]
Gliese & Jahreiß (1991) 294.3 ± 3.5 3.4 ± 0.04 11.08 ± 0.13 [6]
van Altena et al. (1995) 289.5 ± 4.4 3.45 ± 0.05 11.27 ± 0.17 [13]
RECONS TOP100 (2012) 289.5 ± 4.4[note 1] 3.45 ± 0.05 11.27 ± 0.17 [14]

Non-trigonometric distance estimates are marked in italic. The best estimate is marked in bold.

See also[edit]

References[edit]

  1. ^ a b Cutri, R. M.; et al. (June 2003). 2MASS All Sky Catalog of point sources. NASA. Bibcode:2003tmc..book.....C. 
  2. ^ a b c d "The One Hundred Nearest Star Systems". RECONS. Georgia State University. Retrieved 2010-06-30. 
  3. ^ Eggen, O. J.; Greenstein, J. L. (October 1965). "Observations of proper-motion stars. II". Astrophysical Journal 142: 925. Bibcode:1965ApJ...142..925E. doi:10.1086/148362. 
  4. ^ Wilson, Ralph Elmer (1953). General Catalogue of Stellar Radial Velocities. Washington: Carnegie Institution of Washington. Bibcode:1953QB901.W495..... 
  5. ^ a b Salim, Samir; Gould, Andrew (January 2003). "Improved Astrometry and Photometry for the Luyten Catalog. II. Faint Stars and the Revised Catalog". The Astrophysical Journal 582 (2): 1011–1031. arXiv:astro-ph/0206318. Bibcode:2003ApJ...582.1011S. doi:10.1086/344822. 
  6. ^ a b Gliese, W. and Jahreiß, H. (1991). "Gl 866". Preliminary Version of the Third Catalogue of Nearby Stars. Retrieved 2014-10-20. 
  7. ^ Casagrande, Luca; Flynn, Chris; Bessell, Michael (September 2008). "M dwarfs: effective temperatures, radii and metallicities". Monthly Notices of the Royal Astronomical Society 389 (2): 585–607. arXiv:0806.2471. Bibcode:2008MNRAS.389..585C. doi:10.1111/j.1365-2966.2008.13573.x. 
  8. ^ Woitas, J.; Leinert, Ch.; Jahreiß, H.; Henry, T.; Franz, O. G.; Wasserman, L. H.; Leinert; Jahreiß; Henry; Franz; Wasserman (January 2000). "The nearby M-dwarf system Gliese 866 revisited". Astronomy and Astrophysics 353: 253–256. arXiv:astro-ph/9910411. Bibcode:2000A&A...353..253W. 
  9. ^ Delfosse, X. et al. (October 1999), Accurate masses of very low mass stars. II. The very low mass triple system GL 866, Astronomy and Astrophysics 350: L39–L42, arXiv:astro-ph/9909409, Bibcode:1999A&A...350L..39D 
  10. ^ Schmitt, J.H.M.M.; Golub, L.; Harnden, F.R. Jr.; Maxson, C.W.; Rosner, R.; Vaiana, G.S. (March 1985). "An Einstein Observatory X-ray survey of main-sequence stars with shallow convection zones". Astrophysical Journal 290 (Part 1): 307–320. Bibcode:1985ApJ...290..307S. doi:10.1086/162986. 
  11. ^ Bobylev, V. V. (November 2010), Stars outside the Hipparcos list closely encountering the Solar system, Astronomy Letters 36 (11): 816–822, arXiv:1009.4856, Bibcode:2010AstL...36..816B, doi:10.1134/S1063773710110071 
  12. ^ Woolley R.; Epps E. A.; Penston M. J.; Pocock S. B. (1970). "Woolley 866". Catalogue of stars within 25 parsecs of the Sun. Retrieved 2014-10-20. 
  13. ^ Van Altena W. F., Lee J. T., Hoffleit E. D. (1995). "GCTP 5475". The General Catalogue of Trigonometric Stellar Parallaxes, Fourth Edition. Retrieved 2014-10-20. 
  14. ^ "RECONS TOP100". THE ONE HUNDRED NEAREST STAR SYSTEMS brought to you by RECONS (Research Consortium On Nearby Stars). 2012. Retrieved 2014-10-20. 

Notes[edit]

  1. ^ Parallax from van Altena et al. (1995).

External links[edit]