19 62ApJ. . .135. .429A the NationalScienceFoundation. various assumedvaluesofthemassratio,and,onexpectationthatprimaryis made whileoneoftheauthors(H.AA)wasaguestinvestigator attheMountWilsonObservatory. luminosity ofthevisualcompanionfromequivalent widthsoftheHY-Helinesand is Mv^—4.5;(3)thesystemicradialvelocityofßLyraesystemgivesnoevidence However, herealizedthatthisluminositymightbetoohighforthreereasons:(1) and radial-velocitycurvesbecauseofthecontaminationformerbyluminous reiterated thefirstobjectiontohigherluminosity. Boyarchuk(1959)estimatedthe distant ascorrespondstoaluminosityofMv=—7.6.MorerecentlyStruve(1958)has of galacticrotation,althoughsuchevidencewouldbeexpectedifthebinarywereas gives Mvconsiderablyfainterthan—7.6;(2)iftheprincipalvisualcompanion(ADS streams. Kuiper(1941)andothershavetabulatedvaluesoftheradiimassesfor high luminosityandaspectroscopicallyinvisiblesecondary,oftenassumedtobeof derived Mv——2.7fortheprimaryofßLyrae. Struve’s estimateoftheluminosityprimaryfromappearanceitsspectrum the moremassivestar,KuipersuggestedaluminosityforprimaryoíMv=—7.6. spectral typeF. 8868) whichhascomponentslistedinTable1.If some orallofthefivecompanionsto binary system.Thesystemconsistsof,inadditiontothegaseousstreams,aB8starof panions (B,E,andF)yieldmotionsthatareprobablyconsistentwithphysicalassociationßLyrae. 11745 B)toßLyraeisphysicallyassociatedwiththelatter,luminosityof range inmagnitudefrom7.2to152.Previousandnewastrometricmeasuresofthethreebrightestcom- 1958) andhasbeenunusuallyproductiveofinformationongaseousstreamsinaclose Spectroscopic measuresofthesethreecompanionsshowthatonethem(E)isprobablynotamember. Another companion(B)isaspectroscopicbinary,forwhichorbitalelementsarederived.Photoelectric measures showthatthetwofaintestcompanions(CandD)arenotphysicallyassociatedwithßLyrae for ßLyraethatisgreaterthanoftheprimary. distance modulusof7.1mag.,andaluminosity,M,forßLyrae—39.Thisleadstosecondarymass From theassociationofcompanionsBandFwithßLyraewederiveareddening,E-v,0065mag., v B © American Astronomical Society •Provided bytheNASA Astrophysics DataSystem Definitive valuesfortheradiiandmasseshavenotbeendeterminedfromlight- Beta Lyraeisamemberofwell-knownvisual multiple system(ADS11745=ß * ContributionfromtheKittPeakNationalObservatory,No. 13.Thespectroscopicobservationswere f OperatedbytheAssociationofUniversitiesforResearch inAstronomy,Inc,undercontractwith Beta Lyraeisaneclipsingbinarywhichhasbeenextensivelyobserved(e.g.,Struve Beta LyraeisamemberofthevisualmultiplesystemADS11745andhasfivecompanionswhich THE VISUALMULTIPLESYSTEMCONTAININGBETALYRAE* Carnegie InstitutionofWashington,CaliforniaInstituteTechnology Hamilton M.Jeeeers,JamesGibson Lick Observatory,UniversityofCalifornia Mount WilsonandPalomarObservatories Kitt PeakNationalObservatoryf Received September20,1961 Allan R.Sandage Helmut A.Abt I. INTRODUCTION ABSTRACT AND 429 19 62ApJ. . .135. .429A AF AE vent 1891).Afterallowingforthis,wefindtheactualchangesinpositionangle(AP.A./ weighted 5.Least-squareslineshavebeendetermined.Themotionsinpositionangleare number ofmeasuresaveraged,exceptthatrecentphotographichavebeen due primarilytotheeffectofprecession,whichamounts—0°6525percentury(Chau- AB settings, areO''006,0''008,and0''017forplatesnumbered2337,2338,2356,respec- ures onplatestakenwiththeautomaticdouble-starcameraLickObservatory panions willyieldagooddistancemodulus.Itisthepurposeofthispapertopresentnew At) andseparation(Ap/At)thatarelistedinTable3.TheastrometricdataonstarsC tively. Theseerrorsareratherlargebecauseoftheinequalityinmagnitudes. 36-inch refractor.Theinternalmeanerrorofthefinalresults,whichdependonnumerous whether thishopecanbefulfilled. 430 astrometric, spectroscopic,andphotometricmeasuresofthecompanionstoascertain ß Lyraearephysicallyassociatedwithit,thecolor-magnitudediagramforthesecom- (1932). RecentmeasuresarelistedinTable2.Alsotherephotographicmeas- © American Astronomical Society •Provided bytheNASA Astrophysics DataSystem In Figure1allknownmeasuresormeansareplottedwithweightsproportionaltothe Early measuresinthesystemADS11745arecollectedbyBurnham(1906)andAitken Pair H. A.ABT,M.JEFFERS,J.GIBSON,ANDR.SANDAGE F A E B D C Component 1928 05 1959 869 1959 869 1959 852 1959 852 1959 852 1929 58 1929 59 1959 869 1955 69 1949 71 1929 59 Date Recent AstrometricMeasuresinADS11745 2 II. ASTROMETRICMEASURES BD+33°3225 BD-f-33°3222 ß Lyrae ß Lyrae Components ofADS11745 317 506 317 473 318 1 148°8 148 747 148 697 148 70 148 5 148 51 (Epoch) 18 646 18 562 18 3 Name P.A. TABLE 1 TABLE 2 86 042 66 965 45 700 45 76 45''82 86 035 84 99 66 997 66 97 45 718 45 733 45 59 Sep 14 3 13 0 mag ADS 9 0 9 2 3 0 6 7 Measures Position No. 34 34 with A 54 34 54 61 c Angle 3 3 2 3 2 318 247 149 68 19 Present (No.2356) Present (No2338) Present (No2356) Present (No.2338) Present (No.2356) Aller (1930) Present (No2337) Aller (1930) Bottger (1958) Aller (1930) Komendantoff (1935) Kranjc (1951) Separa- from A tion 46" 86 46 67 64 Observer 19 62ApJ. . .135. .429A proper motionandarrowsontheotherstarsindicatingtheirmotionsrelativetoA,after position anglerelativetoAarealsoverysmall,butthemotionsinseparationseembe we haveplottedtoscalethemultiplesystemwithanarrowonA(ßLyrae)indicatingits roughly thesameasthoseinTable3. and Dareinsufficienttodeterminemotions,althoughthoseofstarCprobably allowing fortheprecessioneffect.ForstarBweseethatitswell-determinedmotionrela- that propermotion.ThiscomparisonforstarsEandFislesscertain.Theirmotionsin tive toAisverysmallcomparedwiththelatter’spropermotion,andhenceitsharesin © American Astronomical Society •Provided bytheNASA Astrophysics DataSystem The propermotionofßLyraeisgiven(Jenkins1952)as0''7percentury.InFigure2 MULTIPLE SYSTEM 431 19 62ApJ. . .135. .429A at least,sharesit. we assume(1)thefinaldistancemodulusof7.1mag.,(2)reasonablemassesforcompo- nents A(31.2SDîo)andB(4SJîo),(3)acircularorbitseenpole-on,thentheexpected for bothdimensions(insecondsofarc)andmotions ofarcpercentury).Thearrowoncom- in measuringpairsofstarsthatdiffersomuch(7mag.)brightness.Theelimination appreciable comparedwiththepropermotionofA.However,Figure1showsthat 432 per century.Ontheotherhand,if,insteadofthird assumption,weassumeacircular motion inpositionangleforABis0?162percentury. Theobservedamountis0?108 on componentsB,E,andFshowthemotionsofthosestars relativetoAinthesametimeintervaland ponent A(ßLyrae)indicatestheextrapolatedpropermotion ofthatstarinacentury,whilethearrows rived changesinseparationofthecomponents. expected motioninseparationis0''077percentury comparedwithanobservedamount after removaloftheprecessioneffectThisshowsthatif proper motionofAiswelldetermined,starB, changes inseparationareverypoorlydetermined,undoubtedlybecauseofthedifficulty of 0'i056percentury.Therefore,themotionBrelative toAisreasonableforadouble- orbit seenequator-onandwithcomponentBat, say, 45°tothelineofsight,then star system. the 1879meanseparationforAEand1929AFwouldgreatlyalterde- ever, theirgeneralsimilarity withthatofB,afterallowanceforthepoorer determina- two-body systemisprobably notvalidfortheselessmassive,moredistant stars.How- © American Astronomical Society •Provided bytheNASA Astrophysics DataSystem We canaskwhetherthemotionsinTable3arereasonableforamultiplesystem.If The motionsofEandF are farmoredifficulttopredictbecausetheassumption ofa Fig. 2.—ThepositionsandmotionsofthecomponentsADS11745Thescaleatlowerrightis AE AB Star Pair H. A.ABT,M.JEFFERS,J.GIBSON,ANDR.SANDAGE (Deg/Century) AP A/M +0 166 -0 108 Mean MotionsinADS11745 ("/Century) +0 383 -0 056 Ap/At TABLE 3 AF Star Pair (Deg/Century) AP A/At +0 285 ("/Century) +0 314 Ap/At 19 62ApJ. . .135. .429A X-spectrograph and8-inchcamera(dispersion41A/mm)forpurposesofobtaining about componentDatthispoint. haps C,E,andFmaybemembersofaphysicalsystemwithA;nothingcansaid system. spectral classificationsandradialvelocities.Thewereestimated tions, indicatesthattheirmotionsmayalsobeattributabletomotioninthemultiple as follows.StarBhasX4026muchstrongerthantheKlineand4471somewhat that ofanA8dwarfexcepttheSrulinesatX4077and4215arestrongerthan, than X4481.ItappearstobeanormalB7Vstar.ThespectrumofstarEismostlylike in Figure3.Thecurveispoorly determinedbecausetheobservationsarefew innumber. stars inADS11745arelistedTable4. yielded ameanspectrographcorrectionof—6.8km/sec.Thecorrectedvelocitiesfor respectively, X4045and4226.ItisclassifiedA8p(Sr).ThespectrumofstarFA8-9V. amplitude whichwasdiscoveredtobevariableby H.Plaskett(Plaskett,Harper, Young, andPlaskett1921).Thespectrumofthesecondary isnotseen.Thevelocitiesof its membershipinthephysicalsystem. star Edonotagree.Unlessisavelocityvariable, theseobservationscastdoubton agrees sufficientlywellwiththis,althoughthetwo velocities(meanof+1.3km/sec) between —15and—20km/sec.Thesingleradial velocity(—22.7km/sec)ofstarF radial velocityiswithinabout10km/secofthat ßLyraemaybeaphysicalmember. solutions. Thefinalorbital elementsarelistedinTable5,andthevelocity-curve isshown B inTable4wereanalyzed bythemethodofLehmann-Filhesandseveral least-squares Struve (1958)indicatesthatthesystemicvelocity ofXLyraemaybeslightlyvariable © American Astronomical Society •Provided bytheNASA Astrophysics DataSystem The conclusionsfromtheastrometricobservationsarethatcomponentBandper- Spectra ofstarsB,E,andFwereobtainedwiththeMountWilson60-inchCassegrain The radialvelocitieswerecalibratedwithmeasuresofProcyonandVega,which We canprobablyexpectthatanycomponentofthe multiplesystemwhosemeasured Star B(HD174664=Boss2777BD+33°3224) isaspectroscopicbinaryofsmall F... E Star r Plate No. Xe-4729 4751 4897 4776 4750 5067 4940 4919 4896 4775 5402 5040 4796 5347 Radial VelocitiesinADS11745 III. SPECTROSCOPICMEASURES MULTIPLE SYSTEM433 1959 Oct.12.224 1959 Nov.7177 1959 Oct13192 1960 Mar. 1959 Dec.12097 1959 Oct.11187 1959 Nov.7139 TABLE 4 Date (UT) 13 149 13 105 14 222 12 181 9 154 8 166 5 540 7 501 Corrected (km/sec) Velocity + 12 + 15 -22 7 -20 -20 -28 -26 -18 -24 -24 -22 -28 -32 -38 34 265 33 814 14 625 14 393 Phase 0 606 0 383 Cycle 0 853 0 155 6 817 6 590 6 353 and 19 62ApJ. . .135. .429A fflîo. TheprincipalspectroscopicresultsarecollectedinTable6. mass inthefunction,welearnonlythatfori<90°,secondaryis>0.22 it camefromaspectrumofonlyfairquality,wemaybejustifiedinneglectingit. velocities (Plaskettetal.1921)of1920becausetheperioddeterminedisnotsufficiently internal errorof3.2km/sec.NoattemptwasmadetoincorporatethefourVictoria 434 that ofßLyraeforagreementinmembership.Aftersubstitutingtheexpectedprimary outside thevelocityrangeobservedhereandwillnotfittheseorbitalelements,but,since The meanscatter(p.e.)of1.4km/secintheobservationsislessthanexpected accurate tobridgetheintervaloftime.OneVictoriavelocities(+11.1km/sec)is The systemicvelocity(—29.4km/sec)ofthisbinaryisprobablysufficientlycloseto © American Astronomical Society •Provided bytheNASA Astrophysics DataSystem F. . E B .. H. A.ABT,M.JEFFERS,J.GIBSON,ANDR.SANDAGE Star To =JD2436852014 ¿ =120km/sec P =4.348days 7 =—294km/sec Spectrum A8p (Sr) B7 V A8-9 V Fig. 3.—Theradial-velocitycurveofADS11745B Spectroscopic ResultsinADS11745 Orbital ElementsofADS11745B Intrinsic (B-F)o + 23 +0 24 -0 13 Color TABLE 5 TABLE 6 Mean Radial Velocity (km/sec) + 13 -29 4 -22 7 6 a\ sini=0693X10km fiffl) =0000702Sío co =158?6 ß= 0.25 Possible non-member Probable member Probable member Membership 19 62ApJ. . .135. .429A attempted withthePalomar20-inchreflector.However,itwasfoundthat,itsscale, photometric resultsarelistedinTable7. ultraviolet measuresofthefaintercomponentscouldsometimesnotbeobtained.The ures ofthebackgroundintensityatnumerouspositionsaroundeachstar.Evenso, larger scaleduringtimesofmoderatelygoodseeingandbyinterpolatingbetweenmeas- accurate photometryonthefaintercomponentswasinhibitedbyscatteredlightfrom Instrument ß Lyrae.Thefaintercomponentscouldbemeasuredonlywithatelescopemuch Ay =3Eb-vandEu-b0.7E-v,weobtain the intrinsicmagnitudesandcolorsin mag. forstarsB,E,andF,respectively.Inviewof thedoubtexpressedinlastsection B with theobservedcolorsinTable7indicatesreddenings, Eb-v,of0.05,0.10,and0.08 ones fromJohnsonandMorgan (1953).Weseethatthe(U—B)ocolorofstar Bplacesit sequence starswithB— F>0.2fromSandageandEggen(1959) for thebluer obtained fromstarsBandFonly,namely,Eb-v— 0.065mag.Usingtheusualrelations, on themembershipofstarEinphysicalsystem, thereddeningofsystemwillbe colors andspectraltypes.Theintrinsiccorresponding (JohnsonandMorgan D the lastcolumnofTable7. 1953) tothespectraltypesinTable6arelisted the sametable.Acomparisonofthese B (UT) Date © American Astronomical Society •Provided bytheNASA Astrophysics DataSystem Star Photometric measuresontheU,B,VsystemofcomponentsADS11745were The spacereddeningofthegroupcanbestbeobtained byacomparisonofobserved The color-colordiagram is showninFigure4,togetherwiththecurve for main- + 008 + 032 - 047 - 008 Oct 2 100" 1959 10 17 0 32 0 20 9 82 7 25 May 30 IV. PHOTOMETRICMEASURESANDCONCLUSIONS 1959 20" 0 54 0 08 7 22 Photometric MeasuresinADS11745 June 1 1960 20" -0 46 •0 08 7 20 MULTIPLE SYSTEM June 16 + 105 + 021 + 074 + 122 + 006 + 034 + 033 + 018 TABLE 7 200" 1960 B-V U-B 13 43 10 16 15 13 9 81 V Sept 28 + 085 + 007 + 021 + 036 + 123 + 033 200" 1960 15 18 13 44 10 15 9 81 Sept. 29 + 007 + 020 + 033 + 031 200" 1960 10 16 9 81 + 105 -f 033 + 079 + 122 + 020 + 018 + 007 + 032 - 049 - 008 Means 15 13 43 10 16 9 81 7 22 (B-V)o -I- 027 -1- 014 + 073 + 101 + 116 + 003 + 016 + 026 (U-B)o - 053 - 014 14.96 13 24 Vo 9 62 9 97 7 03 435 19 62ApJ. . .135. .429A system butbeabovethemainsequencebecauseitisanApstar;Eggen(1957)hasshown 436 H.A.ABT,M.JEFFERS,J.GIBSON,ANDR.SANDAGE of E-v=0.065mag.Thecurveisformain-sequencestars. ably fromthezero-agemainsequence.StarEmaystillbeamemberofphysical values oftheinterstellarreddeningwillnotchangethis.Theconclusionsaboutother Eb-v, of0.065mag.andadistance modulusof7.1mag. sequence aredetectablyevolvedoffthezero-agelineandsinceßLyraemustbecloseto stars onlyasmuch3mag.(Sandage1957)belowtheupperterminationofmain of 7.1mag.,starsBandFfitonthezero-agemain-sequenceline(Sandage1957).Since magnitudes andcolorscorrectedforinterstellarreddening.Withatruedistancemodulus by thesecondarystar.StarDdoesnotfitmain-sequenceline,andslightlydifferent made belowthatthemagnitudesandcolorsofthisspectroscopicbinaryarenotaffected directly onthemain-sequenceline.Thisgivesslightsupportforassumptiontobe this termination,itisreasonabletoassumethatstarBwouldnothaveevolveddetect- three starsareuncertain. b © American Astronomical Society •Provided bytheNASA Astrophysics DataSystem The color-magnitudediagramforallstarsinADS11745isshownFigure5,using Fig. 4.—Thecolor-colormeasures(dots)forstarsinADS11745anassumedinterstellarreddening Fig. 5.—Thecolor-magnitude diagramforstarsinADS11745,assuminganinterstellar reddening, 19 62ApJ. . .135. .429A f possible contractingstars(JohnsonandMitchell1958).WeconcludethatstarCisnot system isverysimilarinage,asjudgedbytheupperterminationpoint,toPleiades, Table 8,whereparenthesesindicatesomeuncertainty. a member.Theconclusionsonmembershipinthephysicalsystemaresummarized and thecorrespondingpositiontothatofstarCinPleiadesiswellabove ground star.StarCmaybeastarstillcontractingtothemainsequence.However,this uncertainty inreddeningandthecolor-magnitudediagramfittingisabout±0.2mag. intrinsic magnitudeandcolorsarethenF=3.16,{B—F)o—0.13,{UB)^— Walker 1960)approximatelyV=3.35,B——0.07,andU—0.58.The luminosity ofßLyraeisMy=—3.9.Theprobableerrorinthedueto that suchstarsaregenerallyabovethemainsequence.StarDundoubtedlyisaback- F annular, sincethespectrumofprimarystarisseenthroughouteclipse.Thisleads B to alowluminosityforthesecondarystarrelativeprimary;Kopal(1941)obtains This isinagreementwithStruve’s(1958)estimatebasedontheappearanceofitsspec- E D C preciable lossinmasssinceevolutionfromthemainsequence,wedriveaprimary mass-luminosity relation(Schwarzschild1958)formain-sequencestars,and(4)noap- a ratioof0.136.TheluminositytheprimarystaralonewouldthenbeMy=—3.8. Aller, R.M.1930,A.N.,238,71. Aitken, R.G1932,NewGeneralCatalogueofDoubleStars (‘Publications oftheCarnegieInstitution mass of20.2SDîoThustheinvisiblesecondaryismoremassivethanprimarystar. a brighteningof1.5mag.sinceevolutionfromthemainsequence,(3)application Boyarchuk, A.1959,Astr.Zhur.,36,766;transSovietAstronomy, 3,748,1960. Bottger, G.1958,A.N.,284,177. Arp, H.C.1958,EncyclopediaofPhysics,ed.S.Flügge(Berlin: Springer-Verlag),51,75. of 115Dîo.Theobservedmassfunction8.59Jîo(Struve1958)thenleadstoasecondary trum. Assumingfortheprimary(1)abolometriccorrectionof1.0mag.(Arp1958),(2) Burnham, S.W.1906,AGeneralCatalogueofDoubleStars (“Publications oftheCarnegieInstitution Kitt PeakNationalObservatoryRoyal-McBeeLGP-30 computer. Eggen, O.J.1957,i./.,62,45. 0 Chauvenet, W.1891,AManual ofSphericalandPracticalAstronomy(reprint:NewYork: DoverPublica- —0.62. Withatruedistancemodulusof7.1mag.,theis260parsecs,and © American Astronomical Society •Provided bytheNASA Astrophysics DataSystem The observedmagnitudesandcolorsofßLyraeatmaximumlightare(Wood Most investigators(seeStruve1958)considertheprimaryeclipseofßLyraetobe tions, Inc.1960),2,467. Washington,” No.417). We areindebtedtoDr.D.H.Schulteforperforming theleast-squaressolutionson Washington,” No.5). Star (Member) (Member) (Member) Astrometry Member Conclusions onMembershipinßLyraePhysicalSystem Radial Velocities (Non-member) Member Member MULTIPLE SYSTEM REFERENCES Criteria TABLE 8 Member Member Member Spectra (Member) Non-member Member Member Non-member Photometry (Non-member) Non-member Non-member Member Member Conclusions 437 19 62ApJ. . .135. .429A Johnson, H.L.,andMitchell,R.I.1958,ApJ,128,31. Johnson, H.L.,andMorgan,W.1953,Ap.117,313. Jenkins, L.F.1952,GeneralCatalogueofTrigonometricStellarParallaxes(NewHaven:YaleUniversity Wood, D.B,andWalker,M.F.1960,Ap.J.,131,363. Struve, O.1958,Pub.A.S.P,70,5. Schwarzschild, M.1958,StructureandEvolutionoftheStars(Princeton,N.J.:PrincetonUniversity Sandage, A1951,Ap.J.,125,435. Kranjc, A.1951,Contr.Milano-MerateObs.,NuovaSer.,No.31. Kopal, Z.1941,Ap./.,93,92. 438 H.A.ABT,M.JEFFERS,J.GIBSON,ANDR.SANDAGE Sandage, A.,andEggen,O.J.1959,M.N.,119,278 Kuiper, G.P.1951,Ap/.,93,133. Komendantoff, N.V1935,Pub.PoulkovoObs.,Ser.II,47,67. Plaskett, JS,Harper,W.EYoung,R.K.,andH.1921,Pub.Dom.ApObs.,1,287. © American Astronomical Society •Provided bytheNASA Astrophysics DataSystem Press). Observatory).