{{Short description|Star in the constellation Draco}} {{Starbox begin | name = λ Draconis }} {{Starbox image | image= {{Location mark |image=Draco constellation map.svg|alt=|float=center|width=260 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=λ Draconis |x=942|y=295 }} |caption=Location of λ Draconis (circled) }} {{Starbox observe | epoch = J2000 | constell = [[Draco (constellation)|Draco]] | ra = {{RA|11|31|24.22075}}<ref name=vanLeeuwen2007/> | dec = {{DEC|+69|19|51.8696}}<ref name=vanLeeuwen2007/> | appmag_v = +3.77 to 3.86<ref name=vsx/> }} {{Starbox character | type = asymptotic giant branch<ref name=eggen1992/> | class = M0III-IIIa Ca1<ref name=perkins1989/> | b-v = +1.62<ref name=Johnson1966/> | u-b = +1.97<ref name=Johnson1966/> | r-i = | variable = [[slow irregular variable|slow irregular]]<ref name=Samus2007/> }} {{Starbox astrometry | radial_v = {{Val|+6.58|0.30}}<ref name=Famaey2009/> | prop_mo_ra = −40.97<ref name=vanLeeuwen2007/> | prop_mo_dec = −19.19<ref name=vanLeeuwen2007/> | parallax = 9.79 | p_error = 0.15 | parallax_footnote = <ref name=vanLeeuwen2007/> | absmag_v = {{Val|−1.14|0.033}}<ref name=park2013/> }} {{Starbox detail | source = <ref name=Baines2018/> | mass = {{val|1.53|0.12}} | radius = {{val|69.99|1.06|1.10}} | luminosity = {{val|884|52}} | temperature = {{val|3761|47|fmt=commas}} | gravity = {{Val|1.10|0.05}}<ref name=Tagaki2011/> | metal_fe = 0.00 | rotational_velocity = | age_gyr = {{val|2.33|0.48}} }} {{Starbox catalog | names = {{odlist | name=Giausar | B=λ Dra | F=1 Dra | BD=+70 665 | FK5=433 | HD=100029 | HIP=56211 | HR=4434 | SAO=15532}}<ref name=SIMBAD/> }} {{Starbox reference | Simbad = lam+Dra }} {{Starbox end}} '''Lambda Draconis''' ('''λ Draconis''', abbreviated '''Lam Dra''', '''λ Dra'''), also named '''Giausar''' ({{IPAc-en|'|dʒ|ɔː|z|ɑr}} {{respell|JAW|zar}}),<ref name=Kunitzsch>{{cite book |last1=Kunitzsch |first1=Paul |last2=Smart |first2=Tim |date = 2006 |edition = 2nd rev. |title = A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations |publisher = Sky Pub |location = Cambridge, Massachusetts |isbn = 978-1-931559-44-7 }}</ref><ref name=IAU-LSN/> is a solitary,<ref name=Eggleton2008/> orange-red<ref name=Moore2013/> [[star]] in the northern [[circumpolar constellation]] of [[Draco (constellation)|Draco]]. It is visible to the [[naked eye]] with an [[apparent visual magnitude]] of around +3.8. Based upon an annual [[stellar parallax|parallax]] shift of 9.79 [[milliarcsecond|mas]] as seen from the Earth,<ref name=vanLeeuwen2007/> the star is located around 333 [[light year]]s from the [[Sun]].
[[File:LamDraLightCurve.png|thumb|left|A [[light curve]] for Lambda Draconis, potted from [[MASCARA]] data<ref name="Burggraaff2018"/><ref name="MASCARA"/>]] This is an [[stellar evolution|evolved]] [[red giant]] star on the [[asymptotic giant branch]]<ref name=eggen1992/> with a [[stellar classification]] of M0III-IIIa Ca1.<ref name=perkins1989/> It is a suspected [[slow irregular variable]] with a periodicity of roughly 1,100 days.<ref name=Samus2007/> It has an estimated 1.53 times the [[mass of the Sun]] and a measured radius of 70 times the [[radius of the Sun]]. It is radiating 884 times the [[solar luminosity]] from its [[photosphere]] at an [[effective temperature]] of 3,761 K.<ref name=Baines2018/>
== Nomenclature == λ Draconis ([[Latinisation of names|Latinised]] to ''Lambda Draconis'') is the star's [[Bayer designation]].
It bore the traditional name ''Giausar''<ref name=Kaler/> (also written as ''Gianfar, Giansar and Giauzar'') and ''Juza''.<ref name=Allen1963/> This name comes from the [[Persian language|Persian]] term ''jauzahr'', referring to the [[Orbital node|nodes]] of the Moon's (or any) orbit.<ref name="IAU-CSN-new"/> In 2016, the [[International Astronomical Union]] organized a [[IAU Working Group on Star Names|Working Group on Star Names]] (WGSN)<ref>{{Cite web|url=https://www.iau.org/science/scientific_bodies/working_groups/280/|title=International Astronomical Union {{!}} IAU|website=www.iau.org|access-date=2017-03-31|archive-date=2016-06-10|archive-url=https://web.archive.org/web/20160610172014/https://www.iau.org/science/scientific_bodies/working_groups/280/|url-status=dead}}</ref> to catalogue and standardize proper names for stars. The WGSN approved the name ''Giausar'' for this star on February 1, 2017, and it is now so included in the List of IAU-approved Star Names.<ref name="IAU-LSN"/>
In [[Chinese astronomy|Chinese]], {{lang|zh|紫微右垣}} ({{lang|zh-Latn|Zǐ Wēi Yòu Yuán}}), meaning ''[[Purple Forbidden enclosure|Right Wall of Purple Forbidden Enclosure]]'', refers to an [[asterism (astronomy)|asterism]] consisting of Lambda Draconis, [[Alpha Draconis]], [[Kappa Draconis]], [[24 Ursae Majoris]], [[43 Camelopardalis]], [[Alpha Camelopardalis]] and [[BK Camelopardalis]].<ref>{{in lang|zh}} ''中國星座神話'', written by 陳久金. Published by 台灣書房出版有限公司, 2005, {{ISBN|978-986-7332-25-7}}.</ref> Consequently, the [[Chinese star names|Chinese name]] for Lambda Draconis itself is {{lang|zh|紫微右垣三}} ({{lang|zh-Latn|Zǐ Wēi Yòu Yuán sān}}, {{langx|en|the Third Star of Right Wall of Purple Forbidden Enclosure}}),<ref>{{in lang|zh}} [http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_ala_alz.htm 香港太空館 - 研究資源 - 亮星中英對照表] {{webarchive|url=https://web.archive.org/web/20081025110153/http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_ala_alz.htm |date=2008-10-25 }}, Hong Kong Space Museum. Accessed on line November 23, 2010.</ref> representing {{lang|zh|上輔}} ({{lang|zh-Latn|Shǎngfǔ}}), meaning ''First Minister''.<ref>[http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/e_research_chinengstarzone_b.htm#PrupleForbiddenEnclosure English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name] {{webarchive|url=https://web.archive.org/web/20080924022136/http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/e_research_chinengstarzone_b.htm |date=2008-09-24 }}, Hong Kong Space Museum. Accessed on line November 23, 2010.</ref> 上輔 (Shǎngfǔ) was westernized into ''Sang Poo'' or ''Shaou Poo'' by R.H. Allen.<ref name=Allen1963/>
==Namesakes== [[USS Giansar (AK-111)]] was a [[United States Navy]] [[Crater class cargo ship]] named after the star.
==References== <references> <ref name="Burggraaff2018">{{cite journal | last1=Burggraaff | first1=O. | last2=Talens | first2=G. J. J. | last3=Spronck | first3=J. | last4=Lesage | first4=A. L. | last5=Stuik | first5=R. | last6=Otten | first6=G. P. P. L. | last7=Van Eylen | first7=V. | last8=Pollacco | first8=D. | last9=Snellen | first9=I. A. G. | title=Studying bright variable stars with the Multi-site All-Sky CAmeRA (MASCARA) | journal=Astronomy & Astrophysics |date=September 2018 | volume=617 | pages=A32 | bibcode=2018A&A...617A..32B | doi=10.1051/0004-6361/201833142 | url=https://www.aanda.org/articles/aa/pdf/2018/09/aa33142-18.pdf | access-date=13 December 2024}}</ref>
<ref name="MASCARA">{{cite web | title=ASCC 81872 | url=https://home.strw.leidenuniv.nl/~burggraaff/MASCARA_variables/on_disk/81872.html | publisher=Leiden University | access-date=13 December 2024}}</ref>
<ref name=Baines2018>{{citation | title=Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer | last1=Baines | first1=Ellyn K. | last2=Armstrong | first2=J. Thomas | last3=Schmitt | first3=Henrique R. | last4=Zavala | first4=R. T. | last5=Benson | first5=James A. | last6=Hutter | first6=Donald J. | last7=Tycner | first7=Christopher | last8=Belle | first8=Gerard T. van | display-authors=1 | journal=The Astronomical Journal | volume=155 | at=30 | year=2018 | issue=1 | arxiv=1712.08109 | bibcode=2018AJ....155...30B | doi=10.3847/1538-3881/aa9d8b | s2cid=119427037 | doi-access=free }}.</ref>
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<ref name="IAU-LSN">{{cite web | url=https://www.iau.org/public/themes/naming_stars/ | title=Naming Stars | publisher=IAU.org | accessdate=16 December 2017 | archive-date=10 March 2025 | archive-url=https://web.archive.org/web/20250310063743/https://www.iau.org/public/themes/naming_stars/ | url-status=dead }}</ref>
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<ref name=Johnson1966>{{citation | display-authors=1 | last1=Johnson | 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 | year=1966 | page=99 | bibcode=1966CoLPL...4...99J | postscript=. }}</ref>
<ref name=park2013>{{citation | display-authors=1 | last1=Park | first1=Sunkyung | last2=Kang | first2=Wonseok | last3=Lee | first3=Jeong-Eun | last4=Lee | first4=Sang-Gak | title=Wilson-Bappu Effect: Extended to Surface Gravity | journal=The Astronomical Journal | volume=146 | issue=4 | pages=73 | year=2013 | doi=10.1088/0004-6256/146/4/73 | bibcode=2013AJ....146...73P | arxiv=1307.0592 | s2cid=119187733 | postscript=. }}</ref>
<ref name=Allen1963>{{citation | url=https://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Draco*.html | first1=Richard Hinckley | last1=Allen | year=1963 | title=Star Names — Their Lore and Meaning: Draco, the Dragon | accessdate=2017-05-28 | postscript=. }}</ref>
<ref name=SIMBAD>{{cite simbad | title=lam Dra | accessdate=2017-05-28 | postscript=. }}</ref>
<ref name="IAU-CSN-new">{{cite web |title=IAU Catalog of Star Names |url=https://exopla.net/star-names/modern-iau-star-names/ |access-date=24 April 2025}}</ref>
<ref name=vsx>{{cite web |url=https://vsx.aavso.org/index.php?view=detail.top&oid=43855 |title=Lambda Dra |website=International Variable Star Index |publisher=AAVSO |access-date=2026-05-20 }}</ref>
</references>
{{Stars of Draco|state=collapsed}}
{{Authority control}}
[[Category:M-type giants]] [[Category:Asymptotic-giant-branch stars]] [[Category:Semiregular variable stars]] [[Category:Suspected variables]] [[Category:Draco (constellation)]] [[Category:Bayer objects|Draconis, Lambda]] [[Category:Durchmusterung objects|BD+70 0665]] [[Category:Flamsteed objects|Draconis, 01]] [[Category:Henry Draper Catalogue objects|100029]] [[Category:Hipparcos objects|056211]] [[Category:Bright Star Catalogue objects|4434]] [[Category:Stars with proper names|Giausar]] [[Category:Population I stars]]