Tau Draconis
| Observation data EpochJ2000.0EquinoxJ2000.0(ICRS) | |
|---|---|
| Constellation | Draco |
| Right ascension | 19h15m33.05868s[1] |
| Declination | +73° 21′ 19.6769″[1] |
| Apparent magnitude(V) | 4.45[2] |
| Characteristics | |
| Spectral type | K2 III:[3] |
| U−Bcolor index | +1.45[2] |
| B−Vcolor index | +1.25[2] |
| Astrometry | |
| Radial velocity(Rv) | −33.70[3]km/s |
| Proper motion(μ) | RA:−115.29[1]mas/yr Dec.:+103.23[1]mas/yr |
| Parallax(π) | 22.28 ± 0.50mas[1] |
| Distance | 146 ± 3ly (45 ± 1pc) |
| Absolute magnitude(MV) | +1.19[4] |
| Details | |
| Mass | 1.25[3]M☉ |
| Luminosity | 48[3]L☉ |
| Surface gravity(logg) | 2.00[5]cgs |
| Temperature | 4,413±77[3]K |
| Metallicity[Fe/H] | 0.17±0.06[6]dex |
| Rotational velocity(vsini) | 8[7]km/s |
| Age | 6.48[3]Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Tau Draconis,Latinizedfromτ Draconis,is anastrometric binary[9]starsystem in the northerncircumpolar constellationofDraco.The star is faintly visible to the naked eye, having anapparent visual magnitudeof 4.45.[2]Based upon an annualparallax shiftof 22.28masas measured from Earth,[1]it is located around 146light yearsfrom theSun.Itsproper motionis propelling it across the sky at the rate of 0.176arc secondsper year.[10]
This is aK-typegiant starwith astellar classificationof K2 III:,[3]where the semi-colon indicates some uncertainty about its spectral value. It is consideredmetal-rich[6]star and is past the firstdredge-upphase of its post-main sequenceevolution,although it shows under-abundances of carbon and oxygen in itsspectrum.[5]The star has 1.25[3]times themass of the Sunand is an estimated 6.48[3]billion years old. It is radiating 48[3]times thesolar luminosityfrom its enlargedphotosphereat aneffective temperatureof 4,413 K.[3]
References
[edit]- ^abcdefvan Leeuwen, F. (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.
- ^abcdJohnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars",Communications of the Lunar and Planetary Laboratory,4(99): 99,Bibcode:1966CoLPL...4...99J.
- ^abcdefghijkLuck, R. Earle (September 2015), "Abundances in the Local Region. I. G and K Giants",The Astronomical Journal,150(3): 23,arXiv:1507.01466,Bibcode:2015AJ....150...88L,doi:10.1088/0004-6256/150/3/88,S2CID118505114,88.
- ^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,S2CID119257644.
- ^abMishenina, T. V.; et al. (October 1995), "Chemical composition of five giants with positive CN-indices.",Astronomy and Astrophysics Supplement,113:333,Bibcode:1995A&AS..113..333M.
- ^abTaylor, B. J. (February 2002), "A statistical search for supermetallicity in F, G and K stars",Monthly Notices of the Royal Astronomical Society,329(4): 839–847,Bibcode:2002MNRAS.329..839T,doi:10.1046/j.1365-8711.2002.05046.x.
- ^Bernacca, P. L.; Perinotto, M. (1970), "A catalogue of stellar rotational velocities",Contributi Osservatorio Astronomico di Padova in Asiago,239(1): 1,Bibcode:1970CoAsi.239....1B.
- ^"tau Dra".SIMBAD.Centre de données astronomiques de Strasbourg.Retrieved2017-05-30.
{{cite web}}:CS1 maint: postscript (link) - ^Eggleton, P. P.; Tokovinin, A. A. (September 2008)."A catalogue of multiplicity among bright stellar systems".Monthly Notices of the Royal Astronomical Society.389(2): 869–879.arXiv:0806.2878.Bibcode:2008MNRAS.389..869E.doi:10.1111/j.1365-2966.2008.13596.x.S2CID14878976.
- ^Lépine, Sébastien; Shara, Michael M. (March 2005), "A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog) ",The Astronomical Journal,129(3): 1483–1522,arXiv:astro-ph/0412070,Bibcode:2005AJ....129.1483L,doi:10.1086/427854,S2CID2603568.
