Astronomy:HD 118889

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Short description: Binary star system in the constellation Boötes
HD 118889
Observation data
Equinox J2000.0]] (ICRS)
Constellation Boötes[1]
Right ascension  13h 39m 34.61613s[2]
Declination +10° 44′ 46.5827″[2]
Apparent magnitude (V) 5.57[1] (6.35 + 6.47)‍[3]
Characteristics
Evolutionary stage Main sequence[4][5]
Spectral type F0V[6]
U−B color index +0.045[7]
B−V color index +0.33[7]
Astrometry
Radial velocity (Rv)−25.9±1.9[8] km/s
Proper motion (μ) RA: −114.96[2] mas/yr
Dec.: −11.74[2] mas/yr
Parallax (π)16.67 ± 0.58[2] mas
Distance196 ± 7 ly
(60 ± 2 pc)
Absolute magnitude (MV)+2.40[9]
Orbit[10]
Period (P)22.460±0.019 yr
Semi-major axis (a)0.19983±0.00055″
Eccentricity (e)0.5450±0.0022
Inclination (i)43.50±0.40°
Longitude of the node (Ω)34.58±0.52°
Periastron epoch (T)B 1929.850±0.024
Argument of periastron (ω)
(secondary)		359.93±0.79°
Details
A
Mass1.59[11] M☉
B
Mass1.55[11] M☉
Other designations
BD+11°2589, HD 118889, HIP 66640, HR 5138, SAO 100654, ADS 8987, WDS 13396+1045
Database references
SIMBADdata

HD 118889 is a binary star system in the northern constellation of Boötes. It is faintly visible to the naked eye as a point of light with an apparent visual magnitude of 5.57.[1] The system is located at a distance of approximately 196 light years from the Sun based on stellar parallax,[2] but is drifting closer with a radial velocity of −26 km/s.[8]

The binary components of this system were first measured by S. W. Burnham in 1878 and it was given the discovery code BU 612.[12] The pair are orbiting each other with a period of 22.46 years with an eccentricity (ovalness) of 0.545. The primary component is magnitude 6.35, with the secondary slightly fainter at magnitude 6.47.[3]

A third star, 3.5″ away, is a 12th-magnitude common-proper-motion companion. Any orbit would take over a thousand years.[11]

References

  1. ↑ 1.0 1.1 1.2 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V 
  3. ↑ 3.0 3.1 Malkov, O. Yu. et al. (2012), "Dynamical Masses of a Selected Sample of Orbital Binaries", Astronomy & Astrophysics 546: 5, doi:10.1051/0004-6361/201219774, A69, Bibcode: 2012A&A...546A..69M 
  4. ↑ Schröder, C.; Reiners, Ansgar; Schmitt, Jürgen H. M. M. (January 2009), "Ca II HK emission in rapidly rotating stars. Evidence for an onset of the solar-type dynamo", Astronomy and Astrophysics 493 (3): 1099–1107, doi:10.1051/0004-6361:200810377, Bibcode: 2009A&A...493.1099S, http://goedoc.uni-goettingen.de/goescholar/bitstream/handle/1/9690/aa10377-08.pdf?sequence=2 
  5. ↑ Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics 537: A120, doi:10.1051/0004-6361/201117691, Bibcode: 2012A&A...537A.120Z 
  6. ↑ Royer, F. et al. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics 463 (2): 671–682, doi:10.1051/0004-6361:20065224, Bibcode: 2007A&A...463..671R 
  7. ↑ 7.0 7.1 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data. SIMBAD, Bibcode: 1986EgUBV........0M 
  8. ↑ 8.0 8.1 Holmberg, J. et al. (2007), "The Geneva-Copenhagen survey of the Solar neighbourhood. II. New uvby calibrations and rediscussion of stellar ages, the G dwarf problem, age-metallicity diagram, and heating mechanisms of the disk", Astronomy & Astrophysics 475 (2): 519–537, doi:10.1051/0004-6361:20077221, Bibcode: 2007A&A...475..519H 
  9. ↑ Reiners, Ansgar (January 2006), "Rotation- and temperature-dependence of stellar latitudinal differential rotation", Astronomy and Astrophysics 446 (1): 267–277, doi:10.1051/0004-6361:20053911, Bibcode: 2006A&A...446..267R 
  10. ↑ "Sixth Catalog of Orbits of Visual Binary Stars", United States Naval Observatory, http://www.astro.gsu.edu/wds/orb6/orb6frames.html, retrieved 2021-04-01 
  11. ↑ 11.0 11.1 11.2 Tokovinin, Andrei (2018), "The Updated Multiple Star Catalog", The Astrophysical Journal Supplement Series 235 (1): 6, doi:10.3847/1538-4365/aaa1a5, Bibcode: 2018ApJS..235....6T 
  12. ↑ Mason, Brian D. et al. (February 1999), "Binary Star Orbits from Speckle Interferometry. I. Improved Orbital Elements of 22 Visual Systems", The Astronomical Journal 117 (2): 1023–1036, doi:10.1086/300748, Bibcode: 1999AJ....117.1023M 



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