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HD 118889

From Wikipedia, the free encyclopedia
Binary star system in the constellation Boötes
HD 118889
Observation data
Epoch J2000      Equinox J2000
ConstellationBoötes
Right ascension13h 39m 34.61613s[1]
Declination+10° 44′ 46.5827″[1]
Apparent magnitude (V)5.57[2](6.35 + 6.47)[3]
Characteristics
Evolutionary stageMain sequence[4][5]
Spectral typeF0V[6]
U−Bcolor index+0.045[7]
B−Vcolor index+0.33[7]
Astrometry
Radial velocity (Rv)−25.9±1.9[8] km/s
Proper motion (μ)RA: −114.96[1]mas/yr
Dec.: −11.74[1]mas/yr
Parallax (π)16.67±0.58 mas[1]
Distance196 ± 7 ly
(60 ± 2 pc)
Absolute magnitude (MV)+2.40[9]
Orbit[10]
Period (P)22.460±0.019yr
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°
Periastronepoch (T)B1929.850±0.024
Argument of periastron (ω)
(secondary)
359.93±0.79°
Details
A
Mass1.89±0.03 M[5]
1.41[11] M
Luminosity18.5[5] L
Surface gravity (log g)3.97[11] cgs
Temperature7,080±241[11] K
Rotational velocity (v sin i)144[5] km/s
Age718[11] Myr
Other designations
BD+11° 2589,HD 118889,HIP 66640,HR 5138,SAO 100654,ADS 8987,WDS 13396+1045,BU 612
Database references
SIMBADdata

HD 118889 is abinary star system in the northernconstellation ofBoötes. It is faintly visible to the naked eye as a point of light with anapparent visual magnitude of 5.57.[2] The system is located at a distance of approximately 196 light years from theSun based onstellar parallax,[1] but is drifting closer with aradial velocity of −26 km/s.[8]

The binary components of this system were first measured byS. W. Burnham in 1878 and it was given thediscovery code BU 612.[12] The pair are orbiting each other with aperiod of 22.46 years with aneccentricity (ovalness) of 0.545. The primary component is a magnitude 6.35[3] star with astellar classification of F0V,[6] matching anF-type main-sequence star. It is an estimated 718[11] million years old and is spinning rapidly with aprojected rotational velocity of 144[5] km/s. The star has 1.4–1.9 times the mass of the Sun. The secondary is slightly fainter at magnitude 6.47.[3]

References

[edit]
  1. ^abcdefvan Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction",Astronomy and Astrophysics,474 (2):653–664,arXiv:0708.1752,Bibcode:2007A&A...474..653V,doi:10.1051/0004-6361:20078357,S2CID 18759600.
  2. ^abAnderson, 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. ^abcMalkov, O. Yu.; et al. (2012), "Dynamical Masses of a Selected Sample of Orbital Binaries",Astronomy & Astrophysics,546: 5,Bibcode:2012A&A...546A..69M,doi:10.1051/0004-6361/201219774, A69
  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"(PDF),Astronomy and Astrophysics,493 (3):1099–1107,Bibcode:2009A&A...493.1099S,doi:10.1051/0004-6361:200810377[permanent dead link]
  5. ^abcdeZorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities",Astronomy & Astrophysics,537: A120,arXiv:1201.2052,Bibcode:2012A&A...537A.120Z,doi:10.1051/0004-6361/201117691,S2CID 55586789
  6. ^abRoyer, F.; et al. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions",Astronomy and Astrophysics,463 (2):671–682,arXiv:astro-ph/0610785,Bibcode:2007A&A...463..671R,doi:10.1051/0004-6361:20065224,S2CID 18475298
  7. ^abMermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)",Catalogue of Eggen's UBV Data. SIMBAD,Bibcode:1986EgUBV........0M
  8. ^abHolmberg, 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,arXiv:0707.1891,Bibcode:2007A&A...475..519H,doi:10.1051/0004-6361:20077221,S2CID 119054949
  9. ^Reiners, Ansgar (January 2006), "Rotation- and temperature-dependence of stellar latitudinal differential rotation",Astronomy and Astrophysics,446 (1):267–277,arXiv:astro-ph/0509399,Bibcode:2006A&A...446..267R,doi:10.1051/0004-6361:20053911,S2CID 8642707
  10. ^"Sixth Catalog of Orbits of Visual Binary Stars".United States Naval Observatory. Retrieved2021-04-01.
  11. ^abcdeDavid, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets",The Astrophysical Journal,804 (2): 146,arXiv:1501.03154,Bibcode:2015ApJ...804..146D,doi:10.1088/0004-637X/804/2/146,S2CID 33401607
  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.Bibcode:1999AJ....117.1023M.doi:10.1086/300748.S2CID 122382211.

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