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New asymptotic giant branch models for a range of metallicities

机译:新的渐近巨型分支模型,适用于各种金属

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We present a new grid of stellar model calculations for stars on theAsymptotic Giant Branch between 1.0 and .Our grid consists of 10 chemical mixtures with 5 metallicities between Z=0.0005and Z=0.04, and with both solar-like and -elementenhanced metal ratios for each metallicity. We treat consistently thecarbon-enhancement of the stellar envelopes by using opacity tableswith varying C/O-ratio and by employing theoretical mass loss rates forcarbon stars. The low temperature opacities have been calculatedspecifically for this project. For oxygen stars we use an empiricalmass loss formalism. The third dredge-up is naturally obtained byincluding convective overshooting. Our models reach effectivetemperatures in agreement with earlier synthetic models, which includedapproximative carbon-enriched molecular opacities and show goodagreement with empirically determined carbon-star lifetimes. A fractionof the models could be followed into the post-AGB phase, for which weprovide models in a mass range supplementing previous post-AGBcalculations. Our grid constitutes the most extensive set ofAGB-models, calculated with the latest physical input data and treatingcarbon-enhancement due to the third dredge-up most consistently.Key words: stars: evolution - stars: AGBand post-AGB - stars: interiors
机译:我们提出了一个新的恒星模型的恒星模型计算网格,其渐近巨星分支介于1.0到1.0之间。我们的网格由10种化学混合物组成,其中5种金属的金属含量在Z = 0.0005和Z = 0.04之间,并且像太阳和元素增强的金属比每个金属性。我们通过使用具有不同C / O比的不透明度表并通过对碳星使用理论质量损失率来始终如一地对待恒星包壳的碳增强。低温混浊度是针对此项目专门计算的。对于氧星,我们使用经验质量损失形式主义。通过包括对流超调自然获得第三次疏通。我们的模型达到了与早期合成模型一致的有效温度,早期合成模型包括近似的富碳分子不透明性,并与经验确定的碳星寿命表现出良好的一致性。可以将一部分模型引入AGB后阶段,为此,我们在质量范围内提供了模型,以补充先前的AGB后计算。我们的网格构成了最广泛的AGB模型集,这些模型使用最新的物理输入数据进行计算并由于第三次疏edge而始终如一地处理碳增强作用。关键词:恒星:演化-恒星:AGB和后AGB-恒星:室内

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