Lambda Boötis(λ Boötis,abbreviatedLam Boo,λ Boo), also namedXuange[10](/ˈʃwɛnɡə/[citation needed]), is astarin the northernconstellationofBoötes.Based onparallaxmeasurements, it is approximately 99light-yearsfrom theSun.[1]
  | |
| Observation data EpochJ2000.0EquinoxJ2000.0 | |
|---|---|
| Constellation | Boötes |
| Right ascension | 14h16m23.01880s[1] |
| Declination | +46° 05′ 17.9005″[1] |
| Apparent magnitude(V) | +4.18[2] |
| Characteristics | |
| Spectral type | A0p λB[3] |
| U−Bcolor index | +0.05[2] |
| B−Vcolor index | +0.08[2] |
| Astrometry | |
| Radial velocity(Rv) | −7.9±1.6[4]km/s |
| Proper motion(μ) | RA:−187.33±0.14[1]mas/yr Dec.:159.05±0.11[1]mas/yr |
| Parallax(π) | 32.94 ± 0.16mas[1] |
| Distance | 99.0 ± 0.5ly (30.4 ± 0.1pc) |
| Absolute magnitude(MV) | +1.71±0.23[5] |
| Details | |
| Mass | 1.66+0.19 −0.16[6]M☉ |
| Radius | 1.7[7]R☉ |
| Luminosity | 19.1+9.0 −6.1[6]L☉ |
| Surface gravity(logg) | 4.188[8]cgs |
| Temperature | 8720[9]K |
| Rotational velocity(vsini) | 100[8]km/s |
| Age | 2.8+1.1 −0.8[6]Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Lambda Boötis is a whiteA-typemain sequence dwarfwith anapparent magnitudeof +4.18. It is the prototype of a group of rare stars known asLambda Boötis stars,all of which are dwarf stars with unusually low abundances ofmetalsin theirspectra.Its diameter has been directly measured to be 1.7 times thatof the Sun.[7]
Nomenclature
editλ Boötis(LatinisedtoLambda Boötis) is the star'sBayer designation.
InChinese astronomy,Lambda Boötis is called huyền qua,Pinyin:Xuángē,meaning 'sombre lance', because this star is marking itself and standing alone in theSombre Lanceasterism,Purple Forbidden enclosure(see:Chinese constellations).[11]Huyền qua (Xuángē)westernizedintoHeuen Ko,but that name was assigned toGamma Boötisby R.H. Allen, with the meaning of 'the heavenly spear'.[12]In 2016, the IAU organized aWorking Group on Star Names(WGSN)[13]to catalog and standardize proper names for stars. The WGSN approved the nameXuangefor Lambda Boötis on 30 June 2017 and it is now so included in the List of IAU-approved Star Names.[10]
This star, along with theAselli(Theta Boötis,Iota BoötisandKappa Boötis), wereAl Aulād al Dhiʼbah(ألعولد ألذعب -al aulād al dhiʼb), "the Whelps of the Hyenas".[14]Al Aulād al DhiʼbahorAulad al Thibawas the title of this star in a 1971NASAmemorandum.[15]
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.Vizier catalog entry
- ^abcJohnson, 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.
- ^Abt, Helmut A.; Morrell, Nidia I. (1995)."The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars".Astrophysical Journal Supplement.99:135.Bibcode:1995ApJS...99..135A.doi:10.1086/192182.
- ^Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system".Astronomy Letters.32(11): 759–771.arXiv:1606.08053.Bibcode:2006AstL...32..759G.doi:10.1134/S1063773706110065.S2CID119231169.
- ^Paunzen, E.; et al. (November 2002)."The status of Galactic field λ Bootis stars in the post-Hipparcos era".Monthly Notices of the Royal Astronomical Society.336(3): 1030–1042.arXiv:astro-ph/0207488.Bibcode:2002MNRAS.336.1030P.doi:10.1046/j.1365-8711.2002.05865.x.S2CID2389489.
- ^abcMontesinos, B.; et al. (March 2009), "Parameters of Herbig Ae/Be and Vega-type stars",Astronomy and Astrophysics,495(3): 901–917,arXiv:0811.3557,Bibcode:2009A&A...495..901M,doi:10.1051/0004-6361:200810623,S2CID14972955
- ^abCiardi; et al. (2007),"The Angular Diameter of λ Boötis",The Astrophysical Journal,659(2): 1623–1628,arXiv:astro-ph/0612723,Bibcode:2007ApJ...659.1623C,doi:10.1086/512077,S2CID17861605
- ^abSong, Inseok; Caillault, J.-P.; Barrado y Navascués, David; Stauffer, John R. (February 2001), "Ages of A-Type Vega-like Stars from uvbyβ Photometry",The Astrophysical Journal,546(1): 352–357,arXiv:astro-ph/0010102,Bibcode:2001ApJ...546..352S,doi:10.1086/318269,S2CID18154947
- ^Martínez-Galarza, J. R.; et al. (March 2009), "Infrared Emission by Dust Around λ Bootis Stars: Debris Disks or Thermally Emitting Nebulae?",The Astrophysical Journal,694(1): 165–173,arXiv:0812.2198,Bibcode:2009ApJ...694..165M,doi:10.1088/0004-637X/694/1/165,S2CID14298654
- ^ab"Naming Stars".IAU.org.Retrieved16 December2017.
- ^(in Chinese)AEEA (Activities of Exhibition and Education in Astronomy) thiên văn giáo dục tư tấn võng 2006 niên 6 nguyệt 14 nhậtArchived2011-07-16 at theWayback Machine
- ^Richard Hinckley Allen: Star Names — Their Lore and Meaning: Boötes
- ^"IAU Working Group on Star Names (WGSN)".Retrieved22 May2016.
- ^Allen, R. H.(1963),Star Names: Their Lore and Meaning(Reprint ed.), New York, NY: Dover Publications Inc, p.105,ISBN978-0-486-21079-7,retrieved2010-12-12
- ^Jack W. Rhoads -Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars,Jet Propulsion Laboratory, California Institute of Technology; November 15, 1971