ASTROMETRIC-SPECTROSCOPIC DETERMINATION OF THE ABSOLUTE MASSES英文资料

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1、TheAstronomicalJournal,133:2684Y2695,2007June#2007.TheAmericanAstronomicalSociety.Allrightsreserved.PrintedinU.S.A.ASTROMETRIC-SPECTROSCOPICDETERMINATIONOFTHEABSOLUTEMASSESOFTHEHgMnBINARYSTARHERCULISGuillermoTorresHarvard-SmithsonianCenterforAstrophysics,Cambridge,MA02138,USA;gtorres@cfa.harv

2、ard.eduReceived2006December1;accepted2007February27ABSTRACTThemercury-manganesestarHerisawell-knownspectroscopicbinarythathasbeenthesubjectofarecentstudybyZavalaandcoworkersinwhichtheyresolvedthecompanionusinglong-baselineinterferometry.Thetotalmassofthebinaryisnowfairlywellestablished,butthe

3、combinationofspectroscopywithastrometryhasnotresultedinindividualmassesconsistentwiththespectraltypesofthecomponents.ThemotionofthecenteroflightofHerwasclearlydetectedbytheHipparcossatellite.HerewemakeuseoftheHipparcosintermediatedata(abscissaresiduals)andshowthatbycombiningtheminanoptimalfas

4、hionwiththeinterferometrytheindi-vidualmassescanbeobtainedreliablyusingonlyastrometry.Wereexamineandthenincorporateexistingradialvelocitymeasurementsintotheorbitalsolution,obtainingimprovedmassesof3:050:24and1:6140:066Mthatareconsistentwiththetheoreticalmass-luminosityrelationfromrecentstell

5、arevolutionmodels.Thesemassdeterminationsprovideimportantinformationfortheunderstandingofthenatureofthispeculiarclassofstars.Keywords:binaries:generalbinaries:spectroscopicmethods:dataanalysisstars:chemicallypeculiarstars:fundamentalparametersstars:individual(Herculis)1.INTRODUCTION2003;Dwore

6、tsky&Budaj2000;Leushin1995andreferencestherein).InarecentpaperZavalaetal.(2007)reportedinterferometricWewerepuzzledbythisapparentinconsistencybetweentheobservationsofthemercury-manganesestarHer[HD145389,hmsseeminglypreciseradialvelocitiesandtheastrometry,andweHR6023,HIP79101,J2000:0¼160846:18

7、,J2000:0¼000wonderedwhetherothervelocitymeasurementsavailableintheþ445605:7,spectraltypeB9:p(HgMn),V¼4:22],whichisliteraturemightclarifythesituation.Inaddition,Herwasob-abinarystar.Thisobjectbelongstoaclassofpeculiarnon-servedintheco