QZ Aurigae: An eclipsing cataclysmic variable with a white dwarf of almost equivalent mass to its companion

摘要

WepresentCCDphotometricmonitoringoftheclassicnovaQZ??Aurigae(NovaAur1964)since2008withthe2.4-mtelescopeatLijiangstationofYunnanAstronomicalObservatoryinChina,aswellasthe2.16-mtelescopeandthe85-cmtelescopeatXionglongstationoftheNationalAstronomicalObservatoryinChina.Byutilizingeightneweclipsetimingsandthedatafromthelastliterature,publishedalmost20??yearsago,weconstructtheOa?’Cdiagramofthissystemtoanalyzetheorbitalperiodvariation.Wefindnoevidenceoflong-termorbitalperiodvariationsinQZ??Aur.Moreover,thelightcurvesshowingthemaineclipseprocessofthewhitedwarfsuggestthepresenceofabrightspotcomponentandadisk,ascommonlyfoundinnova-likevariables.Thismayrevealhighmassaccretionandhighmasstransferinthissystem.However,evenhighmasstransferratesfromthedonorareinconsistentwithourresultofnoperiodvariations,unlessthemassratioisalmostequalto1.Hence,theobservedresultsherepossiblysupportthatthemassoftheprimarywhitedwarfisextremelyclosetothatofthedonorstarintheeclipsingbinaryQZ??Aur.