Stellar age determination in the mass-luminosity plane
Stellar age determination in the mass-luminosity plane
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质量-光度平面中的恒星年龄测定
DOI：
10.1093/mnras/stac3141
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发表时间：
2023
影响因子：
4.8
通讯作者：
Higgins E
中科院分区：
文献类型：
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作者：
Higgins E
恒星的年龄在历史上依赖于模型标准化网格的等时线拟合。虽然这些恒星模型对大质量恒星的观测样本提供了关键的限制，但它们继承了许多系统的不确定性，主要是在整个网格中应用的内部混合机制，从根本上破坏了等时线方法。在这项工作中，我们利用Higgins & Vink的质量-亮度（M-L）平面作为确定恒星年龄的方法，混合校正模型应用校准的核心超调αovand旋转速率来拟合观测数据。我们提供了多个测试平台来展示我们的新方法，同时还提供了与常用等时线方法的比较，突出了主要的系统误差。我们重现了单个O型恒星的演化，并分析了VLT火焰狼蛛巡天中O型和B型超巨星的更广泛样本，提供了专门的模型，估计了αov，Ω/Ωcrit，并最终确定了恒星年龄。M-L平面突出了O超巨星样本光谱质量的巨大差异。此外，M-L平面还表明B超巨星样品的演化质量是不适当的。最后，我们利用分离食双星，VFTS 642和VFTS 500，并提出他们的年龄导致其精确的动力学质量，提供了一个机会，以限制其内部混合。对于近TAMS系统，VFTS 500，我们发现这两个组件需要大量的核心超调（α超过0.5），这意味着扩展的主序列宽度。因此，我们推断绝大多数B超巨星仍然在其核心燃烧氢。
The ages of stars have historically relied on isochrone fitting of standardized grids of models. While these stellar models have provided key constraints on observational samples of massive stars, they inherit many systematic uncertainties, mainly in the internal mixing mechanisms applied throughout the grid, fundamentally undermining the isochrone method. In this work, we utilize the mass–lumiosity (M–L) plane of Higgins & Vink as a method of determining stellar age, with mixing-corrected models applying a calibrated core overshooting αovand rotation rate to fit the observational data. We provide multiple test-beds to showcase our new method, while also providing comparisons to the commonly used isochrone method, highlighting the dominant systematic errors. We reproduce the evolution of individual O stars, and analyse the wider sample of O and B supergiants from the VLT-FLAMES Tarantula Survey, providing dedicated models with estimates for αov, Ω/Ωcrit, and ultimately stellar ages. The M–L plane highlights a large discrepancy in the spectroscopic masses of the O supergiant sample. Furthermore the M–L plane also demonstrates that the evolutionary masses of the B supergiant sample are inappropriate. Finally, we utilize detached eclipsing binaries, VFTS 642 and VFTS 500, and present their ages resulting from their precise dynamical masses, offering an opportunity to constrain their interior mixing. For the near-TAMS system, VFTS 500, we find that both components require a large amount of core overshooting (αov≃ 0.5), implying an extended main-sequence width. We hence infer that the vast majority of B supergiants are still burning hydrogen in their cores.