High-Dispersion Spectroscopic Study of Solar Twins: HIP 56948, HIP 79672, and HIP 100963

摘要

Anintensivespectroscopicstudywasperformedforthreerepresentativesolartwins(HIP56948,HIP79672,andHIP100963)aswellasfortheSun(Moon;referencestandard),withintentionsof(1)quantitativelydiscussingtherelative-to-Sunsimilaritiesbasedonthepreciselyestablisheddifferentialparametersand(2)investigatingthereasonthatcausestheLiabundancedifferences,despitetheirsimilarities.ItwasconcludedthatHIP56948mostresemblestheSunineveryrespect,includingtheLiabundance(thoughnotperfectlysimilar)amongthethree,anddeservesthenameofa€?closest-eversolartwina€?,whileHIP79672andHIP100963haveasomewhathighereffectivetemperatureandappreciablyhighersurfaceLicomposition.WhilethereisanindicationofLibeingrotation-dependent,becausetheprojectedrotationinHIP56948(andtheSun)isslightlylowerthantheothertwo,therotationaldifferencealonedoesnotseemtobesolargeastoefficientlyproduceamarkedchangeinLi.Rather,thismaybemorelikelytobeattributed(atleastpartly)toaslightdifferencein$$T_{ meff}$$viasome$$T_{ meff}$$-sensitiveLi-controllingmechanism.SincetheabundanceofBewasfoundtobeessentiallysolarforallstarsirrespectiveofLi,anyphysicalprocesscausingtheLidiversityshouldworkonlyonLiwithoutaffectingBe.