View source for Astronomy:Lambda Boötis

{{short description|Star in the constellation of Boötes}}
{{Starbox begin
| name     = λ Boötis
}}
{{Starbox image
 | image=
{{Location mark
|image=Boötes constellation map.svg|alt=|float=center|width=220
|label=|position=right
|mark=Red circle.svg|mark_width=10|mark_link=λ Boötis
|x=656|y=207
}}
|caption=Location of λ Boötis (circled)
}}
{{Starbox observe
| epoch    = J2000.0
| constell = [[Astronomy:Boötes|Boötes]]
| ra       = {{RA|14|16|23.01880}}<ref name="van Leeuwen2007"/>
| dec      = {{DEC|+46|05|17.9005}}<ref name="van Leeuwen2007"/>
| appmag_v = +4.18<ref name=1966CoLPL_4_99J/>
}}
{{Starbox character
| class    = A0p&nbsp;λB<ref name=abt1995/>
| b-v      = +0.08<ref name=1966CoLPL_4_99J/>
| u-b      = +0.05<ref name=1966CoLPL_4_99J/>
| variable = 
}}
{{Starbox astrometry
| radial_v = {{Val|−7.9|1.6}}<ref name=Gontcharov2006/>
| prop_mo_ra  = {{val|−187.33|0.14}}<ref name="van Leeuwen2007"/>
| prop_mo_dec = {{val|159.05|0.11}}<ref name="van Leeuwen2007"/>
| parallax = 32.94
| p_error  = 0.16
| parallax_footnote = <ref name="van Leeuwen2007"/>
| absmag_v = {{Val|+1.71|0.23}}<ref name=Paunzen2002/>
}}
{{Starbox detail
| mass     = {{val|1.66|+0.19|-0.16}}<ref name=aaa495_3_901/>
| radius   = 1.7<ref name=apj659_2_1623/>
| gravity  = 4.188<ref name=apj546_1_352/>
| luminosity  = {{val|19.1|+9.0|-6.1}}<ref name=aaa495_3_901/>
| temperature = {{val|8,720}}<ref name=apj694_1_165/>
| metal_fe = 
| rotational_velocity = 100<ref name=apj546_1_352/>
| age_gyr  = {{val|2.8|+1.1|-0.8}}<ref name=aaa495_3_901/>
}}
{{Starbox catalog
}}
{{Starbox reference
|Simbad=lam+Boo
}}
{{Starbox end}}
'''Lambda Boötis''' ('''λ Boötis''', abbreviated '''Lam Boo''', '''λ Boo'''), also named '''Xuange'''<ref name="IAU-LSN">{{cite web | url=https://www.iau.org/public/themes/naming_stars/ | title=Naming Stars |publisher=IAU.org |access-date=16 December 2017}}</ref> ({{IPAc-en|ˈ|ʃ|w|ɛ|n|g|ə}}{{cn|date=June 2019}}), is a [[Astronomy:Star|star]] in the northern [[Astronomy:Constellation|constellation]] of [[Astronomy:Boötes|Boötes]]. Based on [[Astronomy:Stellar parallax|parallax]] measurements, it is approximately 99 [[Astronomy:Light-year|light-year]]s from the [[Astronomy:Sun|Sun]].<ref name="van Leeuwen2007"/>

Lambda Boötis is a white [[Astronomy:Stellar classification#Class A|A-type]] [[Astronomy:Main sequence|main sequence dwarf]] with an [[Astronomy:Apparent magnitude|apparent magnitude]] of +4.18. It is the prototype of a group of rare stars known as [[Astronomy:Lambda Boötis star|Lambda Boötis star]]s, all of which are dwarf stars with unusually low abundances of [[Astronomy:Metallicity|metals]] in their [[Physics:Astronomical spectroscopy|spectra]]. Its diameter has been directly measured to be 1.7 times that [[Astronomy:Solar radius|of the Sun]].<ref name=apj659_2_1623>{{Citation| url=http://www.iop.org/EJ/article/0004-637X/659/2/1623/64307.html | author=Ciardi | title=The Angular Diameter of λ Boötis | journal=The Astrophysical Journal | volume=659 | issue=2 | pages=1623–1628 | year=2007 | doi=10.1086/512077 | last2=Van Belle | first2=Gerard T. | last3=Boden | first3=Andrew F. | last4=Ten Brummelaar | first4=T. | last5=McAlister | first5=H. A. | last6=Bagnuolo, Jr. | first6=W. G. | last7=Goldfinger | first7=P. J. | last8=Sturmann | first8=J. | last9=Sturmann | first9=L. | bibcode=2007ApJ...659.1623C|arxiv = astro-ph/0612723 | display-authors=1 | last10=Turner | first10=N. | last11=Berger | first11=D. H. | last12=Thompson | first12=R. R. | last13=Ridgway | first13=S. T. | s2cid=17861605 }}</ref>

==Nomenclature==

''λ Boötis'' ([[Social:Latinisation of names|Latinised]] to ''Lambda Boötis'') is the star's [[Astronomy:Bayer designation|Bayer designation]].

In [[Astronomy:Chinese astronomy|Chinese astronomy]], Lambda Boötis is called 玄戈, [[Pinyin]]: ''Xuángē'', meaning 'sombre lance', because this star is marking itself and standing alone in the ''Sombre Lance'' [[Astronomy:Asterism|asterism]], [[Astronomy:Purple Forbidden enclosure|Purple Forbidden enclosure]] (see : [[Astronomy:Chinese constellations|Chinese constellations]]).<ref>{{in lang|zh}} [http://aeea.nmns.edu.tw/2006/0606/ap060614.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 14 日]</ref> 玄戈 (''Xuángē'') [[Social:Westernization|westernized]] into ''Heuen Ko'', but that name was assigned to [[Astronomy:Gamma Boötis|Gamma Boötis]] by R.H. Allen, with the meaning of 'the heavenly spear'.<ref>[http://www.constellationsofwords.com/stars/Seginus.html Richard Hinckley Allen: Star Names — Their Lore and Meaning: Boötes]</ref> In 2016, the IAU organized a [[Astronomy:IAU Working Group on Star Names|Working Group on Star Names]] (WGSN)<ref name="WGSN">{{cite web | url=https://www.iau.org/science/scientific_bodies/working_groups/280/ | title=IAU Working Group on Star Names (WGSN)|access-date=22 May 2016}}</ref> to catalog and standardize proper names for stars. The WGSN approved the name ''Xuange'' for Lambda Boötis on 30 June 2017 and it is now so included in the List of IAU-approved Star Names.<ref name="IAU-LSN"/>

This star, along with the ''Aselli'' ([[Astronomy:Theta Boötis|Theta Boötis]], [[Astronomy:Iota Boötis|Iota Boötis]] and [[Astronomy:Kappa Boötis|Kappa Boötis]]), were ''Al Aulād al Dhiʼbah'' (ألعولد ألذعب - ''al aulād al dhiʼb''), "the Whelps of the Hyenas".<ref>{{Citation
 | last=Allen
 | first=R. H.
 | year=1963
 | title=Star Names: Their Lore and Meaning
 | url=https://archive.org/details/starnamestheirlo00alle/page/105
 | access-date=2010-12-12
 | edition=Reprint
 | publisher=Dover Publications Inc
 | location=New York, NY
 | isbn=978-0-486-21079-7
 | page=[https://archive.org/details/starnamestheirlo00alle/page/105 105]
 | url-access=registration
 }}</ref> ''Al Aulād al Dhiʼbah'' or ''Aulad al Thiba'' was the title of this star in a 1971 [[Organization:NASA|NASA]] memorandum.<ref>[https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720005197_1972005197.pdf 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]</ref>

==References==
{{reflist|refs=

<ref name=aaa495_3_901>{{citation | display-authors=1 | last1=Montesinos | first1=B. | last2=Eiroa | first2=C. | last3=Mora | first3=A. | last4=Merín | first4=B. | title=Parameters of Herbig Ae/Be and Vega-type stars | journal=Astronomy and Astrophysics | volume=495 | issue=3 | pages=901–917 |date=March 2009 | doi=10.1051/0004-6361:200810623 | bibcode=2009A&A...495..901M |arxiv = 0811.3557 | s2cid=14972955 }}</ref>

<ref name=apj694_1_165>{{citation | display-authors=1 | last1=Martínez-Galarza | first1=J. R. | last2=Kamp | first2=I. | last3=Su | first3=K. Y. L. | last4=Gáspár | first4=A. | last5=Rieke | first5=G. | last6=Mamajek | first6=E. E. | title=Infrared Emission by Dust Around λ Bootis Stars: Debris Disks or Thermally Emitting Nebulae? | journal=The Astrophysical Journal | volume=694 | issue=1 | pages=165–173 |date=March 2009 | doi=10.1088/0004-637X/694/1/165 | bibcode=2009ApJ...694..165M |arxiv = 0812.2198 | s2cid=14298654 }}</ref>

<ref name=apj546_1_352>{{citation | last1=Song | first1=Inseok | last2=Caillault | first2=J.-P. | last3=Barrado y Navascués | first3=David | last4=Stauffer | first4=John R. | title=Ages of A-Type Vega-like Stars from uvbyβ Photometry | journal=The Astrophysical Journal | volume=546 | issue=1 | pages=352–357 |date=February 2001 | doi=10.1086/318269 | bibcode=2001ApJ...546..352S |arxiv = astro-ph/0010102 | s2cid=18154947 }}</ref>

<ref name="van Leeuwen2007">{{cite journal | title=Validation of the new Hipparcos reduction | url=http://www.aanda.org/articles/aa/abs/2007/41/aa8357-07/aa8357-07.html | last1=van Leeuwen | first1=F. | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | date=2007 | arxiv=0708.1752 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 | s2cid=18759600 }} [http://webviz.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=I/311/hip2&recno=69494 Vizier catalog entry ]</ref>

<ref name=abt1995>{{cite journal | bibcode=1995ApJS...99..135A | title=The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars | journal=Astrophysical Journal Supplement | volume=99 | pages=135 | last1=Abt | first1=Helmut A. | last2=Morrell | first2=Nidia I. | year=1995 | doi=10.1086/192182 | doi-access=free }}</ref>

<ref name=1966CoLPL_4_99J>{{Cite journal | last1=Johnson | display-authors=1 | first1=H. L. | last2=Iriarte | first2=B. | last3=Mitchell | first3=R. I. | last4=Wisniewskj | first4=W. Z. | title=UBVRIJKL photometry of the bright stars | journal=Communications of the Lunar and Planetary Laboratory | volume=4 | issue=99 | pages=99 | year=1966 | bibcode=1966CoLPL...4...99J }}</ref>

<ref name=Gontcharov2006>{{Cite journal | last1=Gontcharov | first1=G. A. | title=Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system | journal=Astronomy Letters | volume=32| issue=11| pages=759–771| date=November 2006 | doi=10.1134/S1063773706110065 | bibcode=2006AstL...32..759G | arxiv=1606.08053 | s2cid=119231169 }}</ref>

<ref name=Paunzen2002>{{Cite journal | display-authors=1 | title=The status of Galactic field λ Bootis stars in the post-Hipparcos era | last1=Paunzen | first1=E. | last2=Iliev | first2=I. Kh. | last3=Kamp | first3=I. | last4=Barzova | first4=I. S. | journal=Monthly Notices of the Royal Astronomical Society | volume=336 | issue=3 | pages=1030–1042 | date=November 2002 | doi=10.1046/j.1365-8711.2002.05865.x | bibcode=2002MNRAS.336.1030P | arxiv=astro-ph/0207488 | s2cid=2389489 }}</ref>

}}

==External links==
* {{citation
 | author1=Hoffleit |display-authors=0 | year=1991 | title=HR 5351
 | work=Bright Star Catalogue | edition=5th Revised
 | url=http://webviz.u-strasbg.fr/viz-bin/VizieR-S?HR%205351
 | access-date=2017-09-13 | postscript=. }}
* {{citation
 | url=http://aladin.u-strasbg.fr/AladinPreview?-c=14+16+23.0187%2B46+05+17.900&ident=NLTT+36818&submit=Aladin+previewer
 | title=lam Bo0 | work=Aladin previewer
 | publisher=Centre de Données astronomiques de Strasbourg
 | access-date=2017-09-12 | postscript=. }}

{{Stars of Boötes}}

{{DEFAULTSORT:Lambda Bootis}}
[[Category:A-type main-sequence stars]]
[[Category:Lambda Boötis stars]]
[[Category:Bayer objects|Bootis, Lambda]]
[[Category:Boötes]]
[[Category:Durchmusterung objects]]
[[Category:Flamsteed objects|Bootis, 19]]
[[Category:Gliese and GJ objects|3837]]
[[Category:Henry Draper Catalogue objects|125162]]
[[Category:Hipparcos objects|069732]]
[[Category:Bright Star Catalogue objects|5351]]

{{Sourceattribution|Lambda Boötis}}