Period and Light-Curve Changes in AP Leonis

摘要

WepresentadetailedstudyoftheperiodandlightcurveoftheeclipsingbinaryAPLeo.WehaveinvestigatedtheperiodvariationofthesystemindetailusingamethodproposedbyKalimerisetal.(1994a,b;AAA061.117.039,AAA062.117.142).Theorbitalperiodofthesystemexhibitsaperiodicvariationwhichcontainsfourcomponentswithdifferentfrequencies.Ourresultisverydifferentfromthatofotherinvestigators.Wecomparedlightcurvesobtainedbyothergroups,andfoundthatthelightcurveofthesystemhaschangedconsiderably.Basedonananalysis,weinvestigatedthephysicalmechanismswhichmayunderliethevariationsoftheperiodandthelightcurve,andobtainedsomenewresults.Wehaveconcludedthattherapidlightvariationisprobablycausedbyapulsationofthecommonenvelope,andthatthemechanismcausingthepulsationmaybemasstransferbetweenthetwocomponents,oritsvariation.Inaddition,wehavefoundthatthemasstransferandmagneticactivitymaysimultaneouslyplayanimportantroleinthevariationsintheorbitalperiodandthelightcurveofthesystem.Thepaperconcludeswithadiscussionoftheevolutionofthesystem.