HD 165189

HD 165189 and HD 165190 are components of a visual binary star[5] system located 145[1] light years away in the southern constellation of Corona Australis. It is visible to the naked eye with the primary having an apparent visual magnitude of 4.929±0.025. The system is a member of the Beta Pictoris Moving Group.[3]

HD 165189
Observation data
Epoch J2000      Equinox J2000
Constellation Corona Australis
Right ascension 18h 06m 49.89282s[1]
Declination −43° 25′ 30.8022″[1]
Apparent magnitude (V) 4.92[2]
Spectral type A6 V + A7 V[3]
B−V color index 0.255±0.017[2]
Radial velocity (Rv)−7.80±0.40[2] km/s
Proper motion (μ) RA: +10.990[1] mas/yr
Dec.: −105.742[1] mas/yr
Parallax (π)22.4417 ± 0.1608[1] mas
Distance145 ± 1 ly
(44.6 ± 0.3 pc)
Absolute magnitude (MV)1.81[2]
Period (P)450.0 yr
Semi-major axis (a)2.04″
Eccentricity (e)0.650
Inclination (i)123.1°
Longitude of the node (Ω)85.8°
Periastron epoch (T)1854.7
Argument of periastron (ω)
HD 165189
Mass1.59[5] M
[6] L
[6] K
Rotational velocity (v sin i)104[7] km/s
HD 165190
Mass1.58[5] M
Other designations
CD−43°12272, GC 24649, HIP 88726, CCDM J18068-4325, WDS J18068-4325[8]
HD 165189: HR 6749
HD 165190: HR 6750
Database references

The pair orbit each other with a period of 450 years and a large eccentricity of 0.650.[4] They have a projected separation of 70.1 AU.[5] Both components are A-type main-sequence stars; the primary has a stellar classification of A6 V while the secondary is A7 V.[3] They have similar masses of 1.59 and 1.58 times the mass of the Sun, respectively.[5]


  1. ^ a b c d e f Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051.
  2. ^ a b c d Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  3. ^ a b c Bell, Cameron P. M.; et al. (November 2015), "A self-consistent, absolute isochronal age scale for young moving groups in the solar neighbourhood", Monthly Notices of the Royal Astronomical Society, 454 (1): 593–614, arXiv:1508.05955, Bibcode:2015MNRAS.454..593B, doi:10.1093/mnras/stv1981, S2CID 55297862.
  4. ^ a b Alzner, A.; Argyle, R. (June 2001), "New orbits for WDS 05248-5219, WDS 18068-4325", IAU Commission 26. (Double Stars) Information Circular, 144: 1–2, Bibcode:2001IAUDS.144R...1A.
  5. ^ a b c d e Tokovinin, A.; Kiyaeva, O. (February 2016), "Eccentricity distribution of wide binaries", Monthly Notices of the Royal Astronomical Society, 456 (2): 2070–2079, arXiv:1512.00278, Bibcode:2016MNRAS.456.2070T, doi:10.1093/mnras/stv2825, S2CID 1615080.
  6. ^ a b Zorec, J.; et al. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy and Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
  7. ^ Royer, F.; Gerbaldi, M.; Faraggiana, R.; Gómez, A. E. (January 2002), "Rotational velocities of A-type stars. I. Measurement of v sin i in the southern hemisphere", Astronomy and Astrophysics, 381: 105–121, arXiv:astro-ph/0110490, Bibcode:2002A&A...381..105R, doi:10.1051/0004-6361:20011422, S2CID 13133418.
  8. ^ "CD-43 12272". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-01-07.