{{Short description|Star in the constellation Lupus}} {{Starbox begin}} {{Starbox image | image= {{Location mark |image=Lupus constellation map.svg|alt=|float=center|width=220 |label=|position=right |mark=Red circle.svg|mark_width=12|mark_link=α Lupi |x=739|y=940 }} |caption=Location of α Lupi (circled) }} {{Starbox observe | constell=[[Lupus (constellation)|Lupus]] | epoch=J2000 | ra={{RA|14|41|55.75579}}<ref name="aaa474_2_653" /> | dec={{DEC|–47|23|17.5155}}<ref name="aaa474_2_653" /> | appmag_v=2.30<ref name="clpl4" /> {{nowrap|(2.29 - 2.34<ref name="gcvs" />)}} }} {{Starbox character | class=B1.5 III<ref name="apj157" /> | b-v=−0.20<ref name="clpl4" /> | u-b=−0.88<ref name="clpl4" /> | variable=[[Beta Cephei variable|β Cep]]<ref name="gcvs" /> }} {{Starbox astrometry | radial_v={{val|+5.4|0.6}}<ref name="aaa448" /> | prop_mo_ra=−20.94<ref name="aaa474_2_653" /> | prop_mo_dec=−23.67<ref name="aaa474_2_653" /> | parallax=7.02 | p_error=0.17 | parallax_footnote=<ref name="aaa474_2_653" /> | absmag_v=−4.3<ref name="aaa216_1_44" /> }} {{Starbox detail | mass={{val|10.1|1.0}}<ref name="mnras410_1_190" /> | radius={{solar radius calculator|type=logLT|1=4.26|logLerr=0.02|2=24550|Terr=0|decimals=2}}<ref name="Sharma" />{{efn | name=radius | Applying the [[Stefan–Boltzmann law]] with a nominal [[sun|solar]] [[effective temperature]] of 5,772 [[Kelvin|K]]: :<math>\sqrt{\biggl(\frac{5,772}{24,550}\biggr)^4 \cdot 10^{4.26}} = 7.46\ R_\odot</math>.}} | gravity=3.46<ref name="aaa216_1_44" /> | luminosity={{val|18200|860|820|fmt=commas}}<ref name="Sharma" /> | temperature=24,550<ref name="Sharma" /> | metal_fe=0.04<ref name="aaa433" /> | rotational_velocity=9.5<ref name="Sharma" /> | age_myr=16–20<ref name="aaa448" /> }} {{Starbox catalog | names={{odlist | name=Uridim | B=α Lup | CD=−46°9501 | FK5=541 | HD=129056 | HIP=71860 | HR=5469 | SAO=225128}}<ref name="SIMBAD" /> }} {{Starbox reference|Simbad=alf+Lup}} {{Starbox end}}
'''Alpha Lupi''' (α Lupi, α Lup), also named '''Uridim''',<ref name="IAU-CSN-new"/> is a [[blue giant]] star, and the brightest [[star]] in the southern [[constellation]] of [[Lupus (constellation)|Lupus]]. According to the [[Bortle Dark-Sky Scale]], its [[apparent visual magnitude]] of 2.3<ref name="clpl4" /> makes it readily visible to the naked eye even from highly light-polluted locales. Based upon [[parallax]] measurements made during the [[Hipparcos]] mission,<ref name="hipparcos" /> the star is around {{Convert|460|ly|pc|abbr=off|lk=on}} from the [[Solar System]].<ref name="aaa474_2_653" /> It is one of the nearest [[supernova]] candidates.<ref name="Firestone2014" />
==Visibility== Visible from the [[Southern Hemisphere]] for much of the year, it can also be viewed for a shorter season from the [[tropics|northern tropics]] and from parts of the [[subtropics|northern subtropical]] latitudes.
==Nomenclature== ''α Lupi'' ([[Latinisation of names|Latinised]] to ''Alpha Lupi'') is the star's [[Bayer designation]].
In [[Chinese astronomy|Chinese]], ''Kekouan'' {{lang|zh|騎官}} ({{lang|zh-Latn|Qí Guān}}), meaning ''[[Root (Chinese constellation)|Imperial Guards]]'', refers to an asterism consisting of α Lupi, [[Gamma Lupi|γ Lupi]], [[Delta Lupi|δ Lupi]], [[Kappa Centauri|κ Centauri]], [[Beta Lupi|β Lupi]], [[Lambda Lupi|λ Lupi]], [[Epsilon Lupi|ε Lupi]], [[Mu Lupi|μ Lup]], [[Pi Lupi|π Lupi]], and [[Omicron Lupi|ο Lupi]].<ref name="zh" /> Consequently, the [[Chinese star names|Chinese name]] for α Lupi itself is {{lang|zh|騎官十}} ({{lang|zh-Latn|Qí Guān shí}}, {{langx|en|the Tenth Star of Imperial Guards}}.).<ref name="hk" />
[[Richard Hinckley Allen|R. H. Allen]] described this star as having the Chinese name ''Yang Mun'' or ''Men'' (南門), meaning "the South Gate", in his work ''[[Star Names: Their Lore and Meaning|Star-Names and their Meanings]]''.<ref name="allen" /> In Chinese astronomy, 南門 is located in ''[[Horn (Chinese constellation)|Horn]]'' mansion and consisted of [[Alpha Centauri|α]] and [[Epsilon Centauri|ε]] Centauri. It was referred to as ''Yang Mun'', meaning "the south Gate". Allen also suggested that the Babylonian name for the star was "Kakkab Su-gub Gud-Elim" (Star Left Hand of the Horned Bull).<ref name="allen" />
The [[Sumerian language|Sumerian]] name for the constellation Lupus was UR.IDIM, later alternatively written ''[[Uridimmu]]'' in the [[Akkadian language]]. The [[IAU Working Group on Star Names]] approved the name Uridim for this star on 12 September 2024 and it is now so entered in the IAU Catalog of Star Names.<ref name="IAU-CSN-new"/>
==Characteristics== [[File:AlphaLupLightCurve.png|thumb|left|A [[light curve]] for Alpha Lupi, plotted from ''[[Hipparcos]]'' data<ref name="HIPCurve" />]] Alpha Lupi is a [[Blue giant|giant star]] with a [[stellar classification]] of B1.5 III.<ref name="apj157" /> It has about ten times the mass of the Sun<ref name="mnras410_1_190" /> yet is radiating 18,000 times the Sun's luminosity. The [[stellar atmosphere|outer atmosphere]] has an [[effective temperature]] of 24,550 K,<ref name="Sharma" /> which gives it the blue-white glow of a [[B-type star]]. In 1956 it was identified as a [[Beta Cephei variable]] by [[Bernard Pagel]] and colleagues,<ref name="mnras116_10" /> which means it undergoes periodic changes in luminosity because of pulsations in the atmosphere. The variability period is 0.29585 days,<ref name="aaa433" /> or just over 7 hours, 6 minutes. The magnitude varies by about 0.05 magnitudes, or about 5% of its brightness. A 14th magnitude star situated 26" from Alpha Lupi is listed as a companion in double star catalogues.<ref name="wds" />
This star is a [[proper motion]] member of the Upper Centaurus–Lupus sub-group in the [[Scorpius–Centaurus association|Scorpius–Centaurus]] [[Stellar association|OB association]], the nearest such co-moving association of massive stars to the Sun.<ref name="aaa216_1_44" /> This is a gravitationally unbound stellar association with an estimated age of 16–20 million years. The association is also the source of a bubble of hot gas that contains the Sun, known as the [[Local Bubble]].<ref name="aaa448" />
== Notes == {{Notelist}}
== References == <references> <ref name="HIPCurve">{{cite web |title=Light Curve |url=https://www.cosmos.esa.int/web/hipparcos/java-tools/light-curve |website=Hipparcos ESA |publisher=ESA |access-date=17 February 2022}}</ref>
<ref name="hipparcos">{{citation | display-authors=1 | last1=Perryman | first1=M. A. C. | last2=Lindegren | last3=Kovalevsky | last4=Hoeg | last5=Bastian | last6=Bernacca | last7=Crézé | last8=Donati | last9=Grenon | title=The HIPPARCOS Catalogue | journal=Astronomy & Astrophysics | volume=323 | pages=L49–L52 |date=April 1997 | bibcode=1997A&A...323L..49P}}</ref>
<ref name="aaa474_2_653">{{citation | first=F. | last=van Leeuwen |date=November 2007 | title=Validation of the new Hipparcos reduction | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 |arxiv = 0708.1752 | s2cid=18759600}}</ref>
<ref name="aaa216_1_44">{{citation | last1=de Geus | first1=E. J. | last2=de Zeeuw | first2=P. T. | last3=Lub | first3=J. | title=Physical parameters of stars in the Scorpio-Centaurus OB association | journal=Astronomy and Astrophysics | volume=216 | issue=1–2 | pages=44–61 |date=June 1989 | bibcode=1989A&A...216...44D}}</ref>
<ref name="aaa433">{{citation | last1=Daszyńska-Daszkiewicz | first1=J. | last2=Niemczura | first2=E. | title=Metallicity of mono- and multiperiodic β Cephei stars | journal=Astronomy and Astrophysics | volume=433 | issue=3 |date=April 2005 | pages=1031–1035 | doi=10.1051/0004-6361:20040397 | bibcode=2005A&A...433.1031D | arxiv=astro-ph/0410442 | s2cid=119340011}}</ref>
<ref name="clpl4">{{citation | 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 | date=1966 | bibcode=1966CoLPL...4...99J}}</ref>
<ref name="apj157">{{citation | last1=Hiltner | first1=W. A. | last2=Garrison | first2=R. F. | last3=Schild | first3=R. E. | title=MK Spectral Types for Bright Southern OB Stars | journal=Astrophysical Journal | volume=157 | pages=313–326 |date=July 1969 | doi=10.1086/150069 | bibcode=1969ApJ...157..313H | doi-access=free}}</ref>
<ref name="SIMBAD">{{citation | work=SIMBAD | title=V* alf Lup -- Variable Star of beta Cep type | publisher=[[Centre de Données astronomiques de Strasbourg]] | url=http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=V*+alf+Lup | accessdate=2009-10-26}}</ref> <ref name="mnras116_10">{{citation | last1=Pagel | first1=B. E. J. | title=Results of a search for bright β Cephei variables in the southern sky | journal=[[Monthly Notices of the Royal Astronomical Society]]| volume=116 | pages=10–24 | date=1956 | bibcode=1956MNRAS.116...10P | doi = 10.1093/mnras/116.1.10 | doi-access=free}}</ref>
<ref name="aaa448">{{citation | last1=Jilinski | first1=E. | title=Radial velocity measurements of B stars in the Scorpius–Centaurus association | journal=Astronomy and Astrophysics | volume=448 | issue=3 |date=March 2006 | pages=1001–1006 | doi=10.1051/0004-6361:20041614 | bibcode=2006A&A...448.1001J|arxiv = astro-ph/0601643 | s2cid=17818058 |display-authors=etal}}</ref>
<ref name="mnras410_1_190">{{citation | last1=Tetzlaff | first1=N. | last2=Neuhäuser | first2=R. | last3=Hohle | first3=M. M. | title=A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun | journal=Monthly Notices of the Royal Astronomical Society | volume=410 | issue=1 | pages=190–200 |date=January 2011 | doi=10.1111/j.1365-2966.2010.17434.x | doi-access=free | bibcode=2011MNRAS.410..190T |arxiv = 1007.4883 | s2cid=118629873}}</ref>
<ref name="Firestone2014">{{citation | title=Observation of 23 Supernovae That Exploded <300 pc from Earth during the past 300 kyr | last1=Firestone | first1=R. B. | journal=The Astrophysical Journal | volume=789 | issue=1 | id=29 | pages=11 | date=July 2014 | doi=10.1088/0004-637X/789/1/29 | bibcode=2014ApJ...789...29F | s2cid=122871106 | url=https://zenodo.org/record/895414 | doi-access=free}}</ref>
<ref name="gcvs">{{citation|bibcode=2009yCat....102025S|title=VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007–2013)|journal=VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S|volume=1|pages=02025|last1=Samus|first1=N. N.|last2=Durlevich|first2=O. V.|year=2009|display-authors=etal}}</ref>
<ref name="wds">{{citation|bibcode= 2001AJ....122.3466M|title= The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog|journal= The Astronomical Journal|volume= 122|issue= 6|pages= 3466|last1= Mason|first1= Brian D.|last2= Wycoff|first2= Gary L.|last3= Hartkopf|first3= William I.|last4= Douglass|first4= Geoffrey G.|last5= Worley|first5= Charles E.|year= 2001|doi= 10.1086/323920|doi-access= free}}</ref>
<ref name="zh">{{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>
<ref name="hk">{{in lang|zh}} [http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_m.htm 香港太空館 - 研究資源 - 亮星中英對照表] {{webarchive|url=https://web.archive.org/web/20110130063012/http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_m.htm |date=2011-01-30}}, Hong Kong Space Museum. Accessed on line November 23, 2010]</ref>
<ref name="allen">{{citation | last=Allen | first=R. H. | date=1963 | author-link=Richard Hinckley Allen | title=Star Names: Their Lore and Meaning | edition=Reprint | publisher=Dover Publications Inc. | location=New York, NY | isbn=0-486-21079-0 | page=[https://archive.org/details/starnamestheirlo00alle/page/279 279] | title-link=Star Names: Their Lore and Meaning}}</ref>
<ref name="Sharma">{{cite journal|doi=10.1093/mnras/stac1816 |title=Pulsating B stars in the Scorpius–Centaurus Association with TESS |year=2022 |last1=Sharma |first1=Awshesh N. |last2=Bedding |first2=Timothy R. |last3=Saio |first3=Hideyuki |last4=White |first4=Timothy R. |journal=Monthly Notices of the Royal Astronomical Society |volume=515 |issue=1 |pages=828–840 |doi-access=free |arxiv=2203.02582 | bibcode=2022MNRAS.515..828S}}</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=22 February 2025}}</ref> </references>
{{Stars of Lupus}}
[[Category:Lupus (constellation)]] [[Category:Bayer objects|Lupi, Alpha]] [[Category:Beta Cephei variables]] [[Category:B-type giants]] [[Category:Upper Centaurus Lupus]] [[Category:Bright Star Catalogue objects|5469]] [[Category:Henry Draper Catalogue objects|129056]] [[Category:Hipparcos objects|071860]] [[Category:Durchmusterung objects|CD-46 09501]] [[Category:Stars with proper names|Uridim]] [[Category:Population I stars]] [[Category:Lucidae]] [[Category:Brightest stars]]