EZ Aquarii

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
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
Distance11.1 ± 0.1 ly
(3.40 ± 0.04 pc)
Absolute magnitude (MV)15.64/15.58/16.34[2]
Details
Mass0.11/0.11/0.10[2] M☉
Temperature2,650[7] K
Orbit[8]
PrimaryEZ Aquarii AC
CompanionEZ 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
SIMBADdata

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

EZ Aquarii distance estimates

Source Parallax, mas Distance, pc Distance, ly Distance, Pm Ref.
Woolley et al. (1970) 305±9 3.28+0.1
−0.09		 10.69+0.33
−0.31		 101.2+3.1
−2.9		 [12]
Gliese & Jahreiß (1991) 294.3±3.5 3.4±0.04 11.08±0.13 104.8+1.3
−1.2		 [6]
van Altena et al. (1995) 289.5±4.4 3.45±0.05 11.27±0.17 106.6±1.6 [13]
RECONS TOP100 (2012) 289.5±4.4[note 1] 3.45±0.05 11.27±0.17 106.6±1.6 [14]

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

See also

References

  1. ↑ 1.0 1.1 Cutri, R. M. et al. (June 2003). 2MASS All Sky Catalog of point sources. NASA. Bibcode:2003tmc..book.....C.
  2. ↑ 2.0 2.1 2.2 2.3 "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. ↑ 5.0 5.1 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. ↑ 6.0 6.1 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 ed.). 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

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

External links