HD 118889
| Observation data EpochJ2000EquinoxJ2000 | |
|---|---|
| Constellation | Boötes |
| Right ascension | 13h39m34.61613s[1] |
| Declination | +10° 44′ 46.5827″[1] |
| Apparent magnitude(V) | 5.57[2](6.35 + 6.47)[3] |
| Characteristics | |
| Evolutionary stage | Main sequence[4][5] |
| Spectral type | F0V[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 ± 0.58mas[1] |
| Distance | 196 ± 7ly (60 ± 2pc) |
| 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 | |
| Mass | 1.89±0.03M☉[5] 1.41[11]M☉ |
| Luminosity | 18.5[5]L☉ |
| Surface gravity(logg) | 3.97[11]cgs |
| Temperature | 7,080±241[11]K |
| Rotational velocity(vsini) | 144[5]km/s |
| Age | 718[11]Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 118889is abinary starsystem in the northernconstellationofBoötes.It is faintly visible to the naked eye as a point of light with anapparent visual magnitudeof 5.57.[2]The system is located at a distance of approximately 196light yearsfrom theSunbased onstellar parallax,[1]but is drifting closer with aradial velocityof −26 km/s.[8]
The binary components of this system were first measured byS. W. Burnhamin 1878 and it was given thediscovery codeBU 612.[12]The pair are orbiting each other with aperiodof 22.46 years with aneccentricity(ovalness) of 0.545. The primary component is a magnitude 6.35[3]star with astellar classificationof F0V,[6]matching anF-type main-sequence star.It is an estimated 718[11]million years old and is spinning rapidly with aprojected rotational velocityof 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]- ^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,S2CID18759600.
- ^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,S2CID119257644
- ^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
- ^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]
- ^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,S2CID55586789
- ^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,S2CID18475298
- ^abMermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)",Catalogue of Eggen's UBV Data. SIMBAD,Bibcode:1986EgUBV........0M
- ^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,S2CID119054949
- ^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,S2CID8642707
- ^"Sixth Catalog of Orbits of Visual Binary Stars".United States Naval Observatory.Retrieved2021-04-01.
- ^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,S2CID33401607
- ^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.S2CID122382211.
