Testing pre-main-sequence models: the power of a Bayesian approach
Testing pre-main-sequence models: the power of a Bayesian approach
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DOI：
10.1111/j.1365-2966.2011.19945.x
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发表时间：
2011-10
影响因子：
4.8
通讯作者：
M. Gennaro;P. Moroni;Emanuele Tognelli Max-Planck-Institut fuer Astronomie-Emanuele-Tognelli-Max-Planck-Institut-fuer-102218120;Heidelberg;U. Pisa;I. N. D. F. N. S. Pisa-I.-N.-D.-F.-N.-S.-Pisa-102489794
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作者：
M. Gennaro;P. Moroni;Emanuele Tognelli Max-Planck-Institut fuer Astronomie-Emanuele-Tognelli-Max-Planck-Institut-fuer-102218120;Heidelberg;U. Pisa;I. N. D. F. N. S. Pisa-I.-N.-D.-F.-N.-S.-Pisa-102489794
前主序列(PMS)模型为恒星形成区域的研究提供了宝贵的工具，因为它们允许我们为年轻恒星分配质量和年龄。因此，根据动态确定质量的PMS恒星的观测结果来检验这些模型是非常重要的。我们开发了一种贝叶斯方法来测试当代PMS模型，它允许与观测进行定量比较，在很大程度上取代了广泛使用的等时线和轨迹定性叠加。使用现有的PMS数据，我们测试了最新的PISA PMS模型，与观察结果建立了良好的一致性。数据涵盖了质量范围从∼0.3M到∼3.1M⊙，温度从∼3×103K到∼1.2×104K，光度从∼3×10−2到∼60 L⊙。在大多数情况下，质量被正确地预测在观测值的20%以内，其中一些情况下的差异只有5%。然而，也观察到了一些差异，并进行了批判性的讨论。通过模拟，使用典型的观测误差，我们评估了LOGτSIM−LOGτREC的传播，即模拟的−恢复的单个物体的年龄分布。我们还发现，由于观测误差，双星系统中的恒星被模拟为同世纪，可能会被恢复为非同世纪。假性非共生性的实际比例是模拟的年龄、质量和质量比的复杂函数。我们证明了使用复合年龄概率分布，即组件年龄分布的乘积，可以比单星更精确地恢复系统的年龄。利用这一有价值的工具，我们估算了目前观测到的PMS双星系统的年龄。
Pre-main-sequence (PMS) models provide invaluable tools for the study of star-forming regions as they allow us to assign masses and ages to young stars. Thus, it is of primary importance to test the models against observations of PMS stars with dynamically determined masses. We developed a Bayesian method for testing the present generation of PMS models, which allows for a quantitative comparison with observations, largely superseding the widely used isochrones and tracks qualitative superposition. Using the available PMS data, we tested the newest PISA PMS models, establishing good agreement with the observations. The data cover a mass range from ∼0.3 to ∼3.1 M⊙, temperatures from ∼3 × 103 to ∼1.2 × 104 K and luminosities from ∼3 × 10−2 to ∼60 L⊙. Masses are correctly predicted within 20 per cent of the observed values in most of the cases, and for some of them the difference is as small as 5 per cent. Nevertheless, some discrepancies are also observed and critically discussed. By means of simulations, using typical observational errors, we evaluated the spread of log τsim− log τrec, i.e. simulated − recovered age distribution of the single objects. We also found that stars in binary systems simulated as coeval might be recovered as non-coeval, due to observational errors. The actual fraction of fake non-coevality is a complex function of the simulated ages, masses and mass ratios. We demonstrated that it is possible to recover the systems’ ages with better precision than for single stars using the composite age–probability distribution, i.e. the product of the components’ age distributions. Using this valuable tool, we estimated the ages of the presently observed PMS binary systems.