EZ_Aquarii
EZ Aquarii
Star in the constellation Aquarius
EZ Aquarii is a triple star system 11.1 light-years (3.4 parsecs) from the Sun in the constellation Aquarius within the Milky Way. It is also known as Luyten 789-6, Gliese 866 and LHS 68. It is a variable star showing flares as well as smaller brightness changes due to rotation. The aggregate mass of the system is 0.3262±0.0018 solar masses.[8] All three seem to have masses close to the hydrogen burning mass limit.[10]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 22h 38m 33.73s[1] |
| Declination | −15° 17′ 57.3″[1] |
| Apparent magnitude (V) | 12.38[2] (13.03/13.27/15.07)[3] |
| Characteristics | |
| Spectral type | M5 V[3] |
| B−V color index | +1.96[4] |
| Variable type | Flare star + BY Dra[5] |
| Astrometry | |
| Radial velocity (Rv) | −59.9[6] km/s |
| Proper motion (μ) | RA: +2314[7] mas/yr Dec.: +2295[7] mas/yr |
| Parallax (π) | 293.6 ± 0.9 mas[8] |
| Distance | 11.11 ± 0.03 ly (3.41 ± 0.01 pc) |
| Absolute magnitude (MV) | 14.75[9] (15.33/15.58/17.37)[3] |
| Orbit[10] | |
| 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° |
| Details | |
| EZ Aquarii A | |
| Mass | 0.1187±0.0011[8] M☉ |
| Radius | 0.175[11] R☉ |
| Luminosity | 0.00078[8] L☉ |
| EZ Aquarii C | |
| Mass | 0.0930±0.0008[8] M☉ |
| Luminosity | 0.00012[8] L☉ |
| EZ Aquarii B | |
| Mass | 0.1145±0.0012[8] M☉ |
| Radius | 0.21±0.04[8] R☉ |
| Temperature | 2650±200[8] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
Location of EZ Aquarii in the constellation Aquarius | |
The configuration of the inner binary pair may permit a circumbinary planet to orbit near their habitable zone, however no exoplanets have yet been observed.[14] 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.[15] The ChView simulation shows that currently its nearest neighbouring star is Lacaille 9352 at about 4.1 ly (1.3 pc) from EZ Aquarii.
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.[17] The A and B components of Luyten 789-6 together emit X-rays.[18]
EZ Aquarii A
This star is a red dwarf of type M5V[3] which has a mass of 0.1187±0.0011 solar masses.[8] It has a parallax of 293.6±0.9 mas.[19] Its period in days around EZ Aquarii C is 3.786516±0.000005 d with an eccentricity of 0 which together make up the primary of the system.[19] It has an absolute magnitude at wavelengths centered at 5500 Angstroms of 15.33 making it the brightest of the three.[3] Some alternate designations for it are EZ Aqr, GL 866A, L 789-6 A and LHS 68.
EZ Aquarii B
There is less known about this star compared to A. Its type is likely a type MV[3] with a mass of 0.1145±0.0012 solar masses.[8] It orbits the AC system with a period of 822.6±0.2 d at an eccentricity of 0.439±0.001.[19] It has an absolute magnitude of 15.58, making it dimmer than A but brighter than C.[3] Some alternate designations for it are GL 866B and L 789-6 B.
EZ Aquarii C
Like the other two, this star is likely a type MV[3] with a mass of 0.0930±0.0008 solar masses.[8] It orbits A in a period of 3.786516±0.000005 d with a nearly circular orbit.[19] It is the dimmest of the three with an absolute magnitude of 17.37.[3] An alternate designation for it is GL 866C.
The high proper motion of EZ Aquarii may have been discovered by Willem Jacob Luyten with his automated photographic plate scanner.[20]
- Cutri, R. M.; et al. (June 2003). 2MASS All Sky Catalog of point sources. NASA. Bibcode:2003tmc..book.....C.
- Zacharias, N.; Finch, C. T.; Girard, T. M.; Henden, A.; Bartlett, J. L.; Monet, D. G.; Zacharias, M. I. (2012). "VizieR Online Data Catalog: UCAC4 Catalogue (Zacharias+, 2012)". VizieR On-line Data Catalog: I/322A. Originally Published in: 2012yCat.1322....0Z; 2013AJ....145...44Z. 1322. Bibcode:2012yCat.1322....0Z.
- "The One Hundred Nearest Star Systems". RECONS. Georgia State University. Archived from the original on 2012-05-13. Retrieved 2023-04-15.
- 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.
- Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1: B/gcvs. Bibcode:2009yCat....102025S.
- Wilson, Ralph Elmer (1953). "General Catalogue of Stellar Radial Velocities". Carnegie Institute Washington D.C. Publication. Washington: Carnegie Institution of Washington. Bibcode:1953GCRV..C......0W.
- 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. S2CID 19035401.
- Houdebine, E. R. (2003). "Dynamics of flares on late type dMe stars. IV. Constraints from spectrophotometry in the visible". Astronomy and Astrophysics. 397 (3): 1019. Bibcode:2003A&A...397.1019H. doi:10.1051/0004-6361:20021537.
- Woitas, J.; Leinert, Ch.; Jahreiß, H.; Henry, T.; Franz, O. G.; Wasserman, L. H. (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.
- Routley, Nick (June 26, 2020). "The 44 Closest Stars and How They Compare to our Sun". Visual Capitalist. Retrieved January 5, 2023.
- "EZ Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-12-14.
- Popova, E. A.; Shevchenko, I. I. (April 2016). "On possible circumbinary configurations of the planetary systems of α Centauri and EZ Aquarii". Astronomy Letters. 42 (4): 260–267. Bibcode:2016AstL...42..260P. doi:10.1134/S106377371604006X. S2CID 123811835.
- 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. S2CID 118512652.
- Jevremovic, D.; Butler, C. J.; Drake, S. A.; O'Donoghue, D. (October 1998). "Ultraviolet and optical flares on GL 866". Astronomy and Astrophysics. 338: 1057–1065. Bibcode:1998A&A...338.1057J.
- Delfosse, Xavier; 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.
- 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.
- Ségransan, D.; Delfosse, X.; Forveille, T.; Beuzit, J. -L.; Udry, S.; Perrier, C.; Mayor, M. (2000). "Accurate masses of very low mass stars: III 16 new or improved masses". Astronomy & Astrophysics. 364: 665–673. arXiv:astro-ph/0010585. Bibcode:2000A&A...364..665S.
- "EZ Aquarii 3". www.solstation.com. Retrieved 2023-05-01.
- Image EZ Aquarii
- Solstation provides an orbital animation as well as a visualization of the habitable zone around EZ Aquarii B.