Beta Lyrae

{{short description|Multiple star system in the constellation of Lyra}} {{Starbox begin}} {{Starbox image | image = {{Location mark |image=Lyra constellation map.svg|alt=|float=center|width=250 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=β Lyrae |x=475|y=862 }} | caption = Location of β Lyrae (circled in red) }} {{Starbox observe | epoch = J2000.0 | constell = Lyra | ra = {{RA|18|50|04.79525}}<ref name=aaa474_2_653/> | dec = {{DEC|+33|21|45.6100}}<ref name=aaa474_2_653/> | appmag_v = 3.25 – 4.36<ref name=gcvs/> }} {{Starbox character | class = B6-8II<ref name=bastian2019/><ref name=mourard2018>{{cite journal |bibcode=2018A&A...618A.112M |title=Physical properties of β Lyrae a and its opaque accretion disk |journal=Astronomy and Astrophysics |volume=618 |pages=A112 |display-authors=1 |last1=Mourard |first1=D. |last2=Brož |first2=M. |last3=Nemravová |first3=J. A. |last4=Harmanec |first4=P. |last5=Budaj |first5=J. |last6=Baron |first6=F. |last7=Monnier |first7=J. D. |last8=Schaefer |first8=G. H. |last9=Schmitt |first9=H. |last10=Tallon-Bosc |first10=I. |last11=Armstrong |first11=J. T. |last12=Baines |first12=E. K. |last13=Bonneau |first13=D. |last14=Božić |first14=H. |last15=Clausse |first15=J. M. |last16=Farrington |first16=C. |last17=Gies |first17=D. |last18=Juryšek |first18=J. |last19=Korčáková |first19=D. |last20=McAlister |first20=H. |last21=Meilland |first21=A. |last22=Nardetto |first22=N. |last23=Svoboda |first23=P. |last24=Šlechta |first24=M. |last25=Wolf |first25=M. |last26=Zasche |first26=P. |year=2018 |arxiv=1807.04789 |doi=10.1051/0004-6361/201832952 |s2cid=73647379 }}</ref> + B<ref name=apj684_2_L95/> | b-v = +0.00<ref name=ppc/> | u-b = −0.56<ref name=ppc/> | variable = β Lyr<ref name=gcvs>{{cite journal |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 |display-authors=etal |last1=Samus |first1=N. N. |last2=Durlevich |first2=O. V. |year=2009}}</ref> }} {{Starbox astrometry | component1 = A | radial_v = −19.2<ref name=gcrv1953/> | prop_mo_ra = 1.90<ref name=aaa474_2_653/> | prop_mo_dec = −3.53<ref name=aaa474_2_653/> | parallax = 3.39 | p_error = 0.17 | parallax_footnote = <ref name=aaa474_2_653/> | absmag_v = −3.82<ref name=Anderson2012/> | component2 = B | radial_v2 = {{val|−14|5}}<ref name=gcvrs/> | prop_mo_ra2 = {{val|4.373|0.087}}<ref name=dr2/> | prop_mo_dec2 = {{val|−0.982|0.098}}<ref name=dr2/> | parallax2 = 3.0065 | p_error2 = 0.0542 | parallax_footnote2 = <ref name=dr2/> | absmag_v2 = }} {{Starbox orbit | primary = Aa1 | name = Beta Lyrae Aa2 | reference = <ref name=apj684_2_L95/> | period_unitless = 12.9414&nbsp;days | axis_unitless = {{val|0.865|0.048|ul=mas}} | eccentricity = 0 | inclination = {{nowrap|92.25 ± 0.82}} | node = {{nowrap|254.39 ± 0.83}} | periastron = }} {{Starbox detail | source = <ref name=MNRAS432_1_799/> | component1 = β Lyr Aa1 | mass = {{nowrap|2.97 ± 0.2}} | radius = {{nowrap|15.2 ± 0.2}} | gravity = {{nowrap|2.5 ± 0.1}} | luminosity = 6,500 | temperature = 13,300 | age_myr = 23 | component2 = β Lyr Aa2 | mass2 = {{nowrap|13.16 ± 0.3}} | radius2 = {{nowrap|6.0 ± 0.2}} | gravity2 = {{nowrap|4.0 ± 0.1}} | luminosity2 = 26,300 | temperature2 = {{nowrap|30,000 ± 2,000}} }} {{Starbox catalog | names = Sheliak, Shelyak, Shiliak, WDS&nbsp;18501+3322<ref name=SIMBAD/> | component2 = β Lyrae A | names2 = 10 Lyrae, AAVSO 1846+33, BD+33&nbsp;3223, FK5&nbsp;705, HD&nbsp;174638, HIP&nbsp;92420, HR&nbsp;7106, SAO&nbsp;67451/2 | component3 = β Lyrae B | names3 = HD&nbsp;174664, BD+33&nbsp;3224, SAO&nbsp;67453 }} {{Starbox reference |Simbad=Beta+Lyrae|sn=β Lyrae |Simbad2=ADS+11745+B|sn2=B }} {{Starbox end}}

'''Beta Lyrae''' ('''β Lyrae''', abbreviated '''Beta Lyr''', '''β Lyr''') officially named '''Sheliak''' (Arabic: الشلياق, Romanization: ash-Shiliyāq) (IPA: {{IPAc-en|'|ʃ|iː|l|i|æ|k}}), the traditional name of the system, is a multiple star system in the constellation of Lyra. Based on parallax measurements obtained during the Hipparcos mission, it is approximately {{Convert|960|ly|pc|abbr=off|lk=on}} distant from the Sun.

Although it appears as a single point of light to the naked eye, it actually consists of six components of apparent magnitude 14.3 or brighter. The brightest component, designated Beta Lyrae A, is itself a triple star system, consisting of an eclipsing binary pair (Aa) and a single star (Ab). The binary pair's two components are designated Beta Lyrae Aa1 and Aa2. The additional five components, designated Beta Lyrae B, C, D, E, and F, are currently considered to be single stars.<ref name=SIMBAD/><ref name=SIMBADB/><ref name=SIMBADC/><ref name=SIMBADD/><ref name=SIMBADE/><ref name=SIMBADF/>

==Nomenclature==

''β Lyrae'' (Latinised to ''Beta Lyrae'') is the system's Bayer designation, established by Johann Bayer in his ''Uranometria'' of 1603, and denotes that it is the second brightest star in the Lyra constellation. WDS J18501+3322 is a designation in the Washington Double Star Catalog. The designations of the constituents as ''Beta Lyrae A'', ''B'' and ''C'', or alternatively ''WDS J18501+3322A'', ''B'' and ''C'', and additionally ''WDS&nbsp;J18501+3322D'', ''E'' and ''F'', and those of ''A's'' components - ''Aa1'', ''Aa2'' and ''Ab'' - derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).<ref name="planetnaming">{{cite arXiv |title=On the naming convention used for multiple star systems and extrasolar planets |date=2010 |eprint=1012.0707 |class=astro-ph.SR |last1= Hessman |first1=F. V. |last2= Dhillon |first2=V. S. |last3= Winget |first3=D. E. |last4= Schreiber |first4=M. R. |last5= Horne |first5=K. |last6= Marsh |first6=T. R. |last7= Guenther |first7=E. |last8= Schwope |first8=A. |last9= Heber |first9=U. }}</ref>

Beta Lyrae bore the traditional name ''Sheliak'' (occasionally ''Shelyak'' or ''Shiliak''), derived from the Arabic الشلياق ''šiliyāq'' or ''Al Shilyāk,'' one of the names of the constellation of Lyra in Islamic astronomy.<ref name=allen1899>{{citation | first1=Richard Hinckley | last1=Allen | title=Star-names and their meanings | journal=New York | year=1899 | page=287 | url=https://books.google.com/books?id=5xQuAAAAIAAJ&pg=PA287 | postscript = . | bibcode=1899sntm.book.....A }}</ref> Notably, in Arabic sources the Lyra constellation is primarily referred to as سِلْيَاق (Romanization: ''Siliyāq)'',<ref>{{Cite book |last=Ghaleb |first=Edouard |url=https://archive.org/details/GAL1988ARLA |title=الموسوعة في علوم الطبيعة ، المجلد الثنين |publisher=Dar El-Mashriq Publications |year=1988 |isbn=2-7214-2148-4 |edition=2nd |location=Lebanon |publication-date=1988 |pages=806 |language=ar |trans-title=Encyclopedia of Natural Sciences, vol. 2}}</ref><ref>{{Cite web |title=Al Moqatel - الظواهر الطبيعية في القرآن والسُّنة، النجوم |url=http://www.moqatel.com/openshare/Behoth/Denia9/Ngoom/tab03.doc_cvt.htm |access-date=2024-01-29 |website=www.moqatel.com}}</ref> whereas شلياق (''Šiliyāq'') primarily is used to refer to Beta Lyrae in what might be a form of linguistic reborrowing.<ref>{{Cite web |title=الكوكبات: كوكبة القيثارة |trans-title=The Lyra Constellation |url=https://www.startimes.com/f.aspx?t=11495876 |access-date=2024-01-29 |website=www.startimes.com|date=19 August 2008 }}</ref><ref>{{Cite web |title=النجوم الثنائية |trans-title=Binary Stars |url=https://saaa-sy.yoo7.com/t203-topic |access-date=2024-01-29 |website=saaa-sy.yoo7.com |publisher=Syrian Astronomical Association |language=ar}}</ref> Persian sources on the other hand, do refer to the Lyra constellation as شلياق (''Šiliyāq''), which may be the source of this confusion.<ref>{{Cite web |last=آزادگان |first=علی |date=2006-10-11 |title=صورتهاي فلكي فصل تابستان |trans-title=Summer Constellations |url=https://www.aliazadegan.com/2006/10/blog-post_11.html |archive-url=https://web.archive.org/web/20140204205620/https://www.aliazadegan.com/2006/10/blog-post_11.html |archive-date=2014-02-04 |access-date=2024-01-29 |language=fa}}</ref><ref>{{Cite web |title=معرفی و رصد صورت فلکی شلیاق و ستاره ی نسرواقع |trans-title=Introducing and observing a loose constellation and a real star. |url=http://nssri.ir/news/245-%D9%85%D8%B9%D8%B1%D9%81%DB%8C-%D9%88-%D8%B1%D8%B5%D8%AF-%D8%B3%D8%AA%D8%A7%D8%B1%DA%AF%D8%A7%D9%86-%D8%AF%D8%B1%D8%AE%D8%B4%D8%A7%D9%86.html |archive-url=https://web.archive.org/web/20240129091510/http://nssri.ir/programsobssubjects/245-%D9%85%D8%B9%D8%B1%D9%81%DB%8C-%D9%88-%D8%B1%D8%B5%D8%AF-%D8%B3%D8%AA%D8%A7%D8%B1%DA%AF%D8%A7%D9%86-%D8%AF%D8%B1%D8%AE%D8%B4%D8%A7%D9%86.html |archive-date=2024-01-29 |access-date=2024-01-29 |website=موسسه علمی پژوهشی نجم شمال |publisher=North Star Scientific Research Institute |language=fa}}</ref>

In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)<ref name="WGSN">{{citation | url=https://www.iau.org/science/scientific_bodies/working_groups/280/ | title=IAU Working Group on Star Names (WGSN) | publisher=International Astronomical Union | access-date=22 May 2016 | postscript=. | archive-date=10 June 2016 | 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 decided to attribute proper names to individual stars rather than entire multiple systems.<ref name="TriRpt18">{{cite web | url=https://www.iau.org/static/science/scientific_bodies/working_groups/280/wg-starnames-triennial-report-2015-2018.pdf | page=5 | title=WG Triennial Report (2015-2018) - Star Names | access-date=2018-07-14 | archive-date=2019-08-23 | archive-url=https://web.archive.org/web/20190823174756/https://www.iau.org/static/science/scientific_bodies/working_groups/280/wg-starnames-triennial-report-2015-2018.pdf | url-status=dead }}</ref> It approved the name ''Sheliak'' for the component Beta Lyrae Aa1 on 21 August 2016 and it is now so included in the List of IAU-approved Star Names.<ref name="IAU-LSN">{{cite web|title=Naming Stars|url=https://www.iau.org/public/themes/naming_stars/|access-date=18 June 2018|publisher=IAU.org|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>

In Chinese astronomy, ''Tsan Tae'' ({{lang|zh|漸台}} ({{lang|zh-Latn|Jiāntāi}}), meaning ''Clepsydra Terrace'', refers to an asterism consisting of this star, Delta² Lyrae, Gamma Lyrae and Iota Lyrae.<ref name=sb0>{{in lang|zh}} [http://aeea.nmns.edu.tw/2006/0607/ap060703.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 3 日] {{Webarchive|url=https://web.archive.org/web/20110521232833/http://aeea.nmns.edu.tw/2006/0607/ap060703.html |date=2011-05-21 }}</ref> Consequently, the Chinese name for Beta Lyrae itself is {{lang|zh|漸台二}} ({{lang|zh-Latn|Jiāntāièr}}, {{langx|en|the Second Star of Clepsydra Terrace}}.)

==Properties== Beta Lyrae Aa is a semidetached binary system made up of a stellar class B6-8 primary star and a secondary that is probably also a B-type star. The fainter, less massive star in the system was once the more massive member of the pair, which caused it to evolve away from the main sequence first and become a giant star. Because the pair are in a close orbit, as this star expanded into a giant it filled its Roche lobe and transferred most of its mass over to its companion.

The secondary, now more massive star is surrounded by an accretion disk from this mass transfer, with bipolar, jet-like features projecting perpendicular to the disk.<ref name=apj684_2_L95/> This accretion disk blocks humans' view of the secondary star, lowering its apparent luminosity and making it difficult for astronomers to pinpoint what its stellar type is. The amount of mass being transferred between the two stars is about {{nowrap|2 × 10⁻⁵ }}solar masses per year, or the equivalent of the Sun's mass every 50,000 years, which results in an increase in orbital period of about 19 seconds each year. The spectrum of Beta Lyrae shows emission lines produced by the accretion disc. The disc produces around 20% of the brightness of the system.<ref name=apj684_2_L95/>

In 2006, an adaptive optics survey detected a possible third companion, Beta Lyrae Ab. It was detected at 0.54" angular separation with a differential magnitude of +4.53. The difference in magnitudes suggests its spectral class is in the range B2-B5 V. This companion would make Beta Lyrae A a hierarchical triple system.<ref>{{Cite journal|last1=Roberts|first1=Lewis C. Jr.|last2=Turner|first2=Nils H.|last3=ten Brummelaar|first3=Theo A.|date=2006|title=Adaptive Optics Photometry and Astrometry of Binary Stars. II A Multiplicity Survey of B Stars|journal=The Astronomical Journal|volume=133|issue=2|pages=545–552|doi=10.1086/510335|bibcode=2007AJ....133..545R |doi-access=free}}</ref>

==Variability== [[File:BetaLyrLightCurve.png|thumb|left|A light curve for Beta Lyrae, plotted from ''TESS'' data<ref name=MAST/>]] The variable luminosity of this system was discovered in 1784 by the British amateur astronomer John Goodricke.<ref name=jha10_23/> In 1894, Aristarkh Belopolsky identified Beta Lyrae as an eclipsing spectroscopic binary.<ref name=philsci_27/> The orbital plane of this system is nearly aligned with the line of sight from the Earth, so the two stars periodically eclipse each other. This causes Beta Lyrae to regularly change its apparent magnitude from +3.2 to +4.4 over an orbital period of 12.9414&nbsp;days. It forms the prototype of a class of ellipsoidal "contact" eclipsing binaries.<ref name=gcvs/>

The two components are so close together that they cannot be resolved with optical telescopes, forming a spectroscopic binary. In 2008, the primary star and the accretion disk of the secondary star were resolved and imaged using the CHARA Array interferometer<ref name=apj628_453/> and the Michigan InfraRed Combiner (MIRC)<ref name=spie62681P/> in the near infrared H band (see video below), allowing the orbital elements to be computed for the first time.<ref name=apj684_2_L95/>

In addition to the regular eclipses, the system shows smaller and slower variations in brightness. These are thought to be caused by changes in the accretion disc and are accompanied by variation in the profile and strength of spectral lines, particularly the emission lines. The variations are not regular but have been characterised with a period of 282 days.<ref name=carrier>{{cite journal|doi=10.1051/0004-6361:20020174 |title=Search for duplicity in periodic variable Be stars |journal=Astronomy and Astrophysics |volume=385 |issue=2 |page=488 |year=2002 |last1=Carrier |first1=F. |last2=Burki |first2=G. |last3=Burnet |first3=M. |bibcode = 2002A&A...385..488C |doi-access=free }}</ref>

The date of a primary minimum can be calculated according the following formula:

Primary_Minimum = 2436793.48 + 12.93095*n + 0.00000386*n*n

whereby n is a natural number. The calculated date is given in Julian days.

==Companions== In addition to Beta Lyrae A, several other companions have been catalogued. β Lyr B, at an angular separation of 45.7", is of spectral type B7V, has an apparent magnitude of +7.2, and can easily be seen with binoculars. It is about 80 times as luminous as the Sun. In 1962 it was identified as spectroscopic binary with a period of 4.348 days,<ref>{{cite journal|date=September 20, 1961|author1= Abt, Helmut A. | author2=Jeffers, Hamilton M. |author3=Gibson, James |author4=Sandage, Allan R.|title=The Visual Multiple System Containing Beta Lyrae|journal= The Astrophysical Journal |volume= 135 |page= 429 |bibcode= 1962ApJ...135..429A|doi=10.1086/147282}}</ref> but the 2004 release of the SB9 catalog of Spectroscopic Binary Orbits omitted it, so it is now considered a single star.<ref name="SIMBADB" />

The next two brightest components are E and F. β Lyr E is magnitude 10.1v, separation 67", and β Lyr F is magnitude 10.6v, separation 86". Both are chemically peculiar stars;<ref name="skiff">{{cite journal|last1=Skiff|first1=B. A.|year=2014|title=VizieR Online Data Catalog: Catalogue of Stellar Spectral Classifications (Skiff, 2009-2016)|journal=VizieR On-line Data Catalog|bibcode=2014yCat....1.2023S}}</ref> both are catalogued as Ap stars, although component F is sometimes thought to be an Am star.<ref name=abt/>

The Washington Double Star Catalog lists two fainter companions, C and D, at 47" and 64" separation, respectively.<ref name="wds">{{cite journal|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|page=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> Component C has been observed to vary in brightness by over a magnitude, but the type of variability is not known.<ref name="proust">{{cite journal|last1=Proust|first1=D.|last2=Ochsenbein|first2=F.|last3=Pettersen|first3=B. R.|year=1981|title=A catalogue of variable-visual binary stars|journal=Astronomy and Astrophysics Supplement Series|volume=44|page=179|bibcode=1981A&AS...44..179P}}</ref>

Components A, B, and F are thought to be members of a group of stars around β Lyrae, at approximately the same distance and moving together. The others just happen to be in the same line of sight.<ref name="abt">{{cite journal|bibcode=1976AJ.....81..659A|title=Visual multiples. III. ADS 11745 (beta Lyrae group)|journal=The Astronomical Journal|volume=81|page=659|last1=Abt|first1=H. A.|last2=Levy|first2=S. G.|year=1976|doi=10.1086/111936|doi-access=free}}</ref> Analysis of Gaia Data Release 2 astrometry reveals a group of about 100 stars around β Lyrae which share its space motion and are at the same distance. This cluster has been named Gaia 8. The cluster members are all main sequence stars and the lack of a main sequence turnoff means that a precise age cannot be calculated, but the cluster age is estimated at 30 to 100 million years. The average Gaia DR2 parallax for the member stars is {{val|3.4|ul=mas}}.<ref name="bastian2019" />

The Gaia spacecraft has provided these data for the stars listed in the WDS: {| class="wikitable plainrowheaders sortable" |- ! scope="col" style="width:30px;" rowspan=2 | Component<ref>{{cite simbad|title=ADS 11745}}</ref> ! scope="col" style="width:70px;" rowspan=2 | Spectral Class ! scope="col" style="width:110px;" rowspan=2 | Magnitude (G) ! scope="col" style="width:330px;" colspan=2 | Proper Motion ! scope="col" style="width:150px;" rowspan=2 | Radial Velocity (km/s) ! scope="col" style="width:150px;" rowspan=2 | Parallax (mas) ! scope="col" style="width:50px;" rowspan=2 | Simbad |- ! scope="col" style="width:150px;" |RA (mas/yr) ! scope="col" style="width:180px;" |δ (mas/yr) |- ! scope="row" | A<ref>{{cite DR2|2090687795054381056}}</ref>{{efn|Gaia DR2 astrometric quality considered to be "terrible" for β Lyr A<ref name=bastian2019>{{cite journal |doi=10.1051/0004-6361/201936595 |arxiv=1909.04612 |title=Gaia 8: Discovery of a star cluster containing β Lyrae |journal=Astronomy & Astrophysics |volume=630 |pages=L8 |year=2019 |last1=Bastian |first1=U. |bibcode=2019A&A...630L...8B |doi-access=free }}</ref>}} | | 3.25 – 4.36 | align=right | 2.045 ± 0.18 | align=right | -3.685 ± 0.2069 | align=right | 2.20 ± 0.7 | align=right | 3.5982 ± 0.1836 |<ref name=SIMBAD/> |- ! scope="row" | B<ref name="dr2"/> | B7V | 7.19 | align=right | 2.174 ± 0.09 | align=right | -1.272 ± 0.1039 | align=right | -14 ± 5 | align=right | 3.5125 ± 0.0898 |<ref name=SIMBADB/> |- ! scope="row" | C<ref>{{cite DR2|2090734696097241344}}</ref> | B2 | 13.07 | align=right | -1.936 ± 0.01 | align=right | -1.934 ± 0.0129 | align=right | ? | align=right | 0.2884 ± 0.0104 |<ref name=SIMBADC/> |- ! scope="row" | D<ref>{{cite DR2|2090688104292041600}}</ref> | K3V | 14.96 | align=right | 0.024 ± 0.034 | align=right | -17.781 ± 0.0409 | align=right | ? | align=right | 0.845 ± 0.0333 |<ref name=SIMBADD/> |- ! scope="row" | E<ref>{{cite DR2|2090734730457641216}}</ref> | G5 | 9.77 | align=right | 1.841 ± 0.015 | align=right | 0.536 ± 0.0159 | align=right | 1.4 | align=right | 1.5737 ± 0.0155 |<ref name=SIMBADE/> |- ! scope="row" | F<ref>{{cite DR2|2090735108414133120}}</ref> | G5 | 10.10 | align=right | 1.416 ± 0.013 | align=right | -3.963 ± 0.0149 | align=right | -16.83 ± 1.41 | align=right | 3.4897 ± 0.0133 |<ref name=SIMBADF/> |} {{notelist}}

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<ref name=SIMBAD>{{citation | title=bet Lyr -- Eclipsing binary of beta Lyr type | work=SIMBAD | publisher=Centre de Données astronomiques de Strasbourg | url=http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Beta+Lyrae | access-date=2018-07-06 | postscript = . }}</ref>

<ref name=SIMBADB>{{citation | title=bet Lyr B -- Star | work=SIMBAD | publisher=Centre de Données astronomiques de Strasbourg | url=http://simbad.u-strasbg.fr/simbad/sim-id?Ident=WDS+J18501%2B3322B | access-date=2018-07-06 | postscript = . }}</ref>

<ref name=SIMBADC>{{citation | title=bet Lyr C -- Star | work=SIMBAD | publisher=Centre de Données astronomiques de Strasbourg | url=http://simbad.u-strasbg.fr/simbad/sim-id?Ident=WDS+J18501%2B3322C | access-date=2018-07-06 | postscript = . }}</ref>

<ref name=SIMBADD>{{citation | title=UCAC3 247-141831 -- Star | work=SIMBAD | publisher=Centre de Données astronomiques de Strasbourg | url=http://simbad.u-strasbg.fr/simbad/sim-id?Ident=WDS+J18501%2B3322D | access-date=2018-07-06 | postscript = . }}</ref>

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== External links == * {{citation | first1=James B. | last1=Kaler | title=The hundred greatest stars | series=Copernicus Series | year=2002 | publisher=Springer | isbn=978-0-387-95436-3 | page=29 | url=https://books.google.com/books?id=aJavy9Yk1yoC&pg=PA29 }} * Philippe Stee's homepage: [http://www.oca.eu/stee/page1/page3/page3.html Hot and Active Stars Research] * {{citation | first=James B. | last=Kaler | title=SHELIAK (Beta Lyrae) | work=Stars | publisher=University of Illinois | url=http://stars.astro.illinois.edu/sow/sheliak.html | access-date=2011-12-20 }} * {{citation | first1=Dan | last1=Bruton | first2=Robb | last2=Linenschmidt | first3=Richard W. | last3=Schmude, Jr. | publisher=Texas A&M University | title=Watching Beta Lyrae Evolve | url=http://www.physics.sfasu.edu/astro/betalyra/ | archive-url=https://web.archive.org/web/20030225014807/http://www.physics.sfasu.edu/astro/betalyra/ | archive-date=2003-02-25 | access-date=2011-12-20 }} * {{citation | first1=Sara J. | last1=Beck | date=July 1, 2011 | title=Beta Lyrae | publisher=AAVSO | url=http://www.aavso.org/vsots_betalyr | access-date=2011-12-20 }}

{{Stars of Lyra}}

Category:Lyra Category:Beta Lyrae variables Lyrae, Beta 6 Category:B-type main-sequence stars Category:Spectroscopic binaries Sheliak Category:Articles containing video clips 174638 7106 BD+33 3223 092420 Category:Be stars Lyrae, 10 Category:B-type bright giants