论文标题

基准测试台面等质激素针对hyades单星序列

Benchmarking MESA isochrones against the Hyades single star sequence

论文作者

Brandner, Wolfgang, Calissendorff, Per, Kopytova, Taisiya

论文摘要

根据Gaia EDR3,我们在Hyades Open Cluster中重新访问和更新我们的真正的单星样本。视差和EDR3的光度法中的小观测不确定性导致了紧密定义的恒星序列,这是理论恒星进化轨道和等速线龙的测试和校准的理想选择。我们针对单星序列基准了太阳尺度的台面进化模型。我们发现,[Fe/H] = +0.25的非旋转MESA模型非常适合质量高于0.85的恒星,而质量恒星非常低,低于0.25 m $ _ $ _ \ odot $。对于质量在0.25至0.85 m $ _ \ odot $的恒星中,模型在系统下预测了观察到的恒星光度。比0.35 m $ _ \ odot $更大的部分模型的一个潜在局限性是(超级充满)对流的处方,与混合长度理论参数$α_ {\ rm ml} $调谐以匹配太阳能模型。低于0.35 m $ _ \ odot $,恒星序列中增加的散射可能是对流接吻不稳定性的体现,这是由于对流核心对信封边界的核能造成的$^3 $ HE HE核能生产率的驱动。对于类似羟那样的恒星种群,太阳能模型在生产质量恒星中的应用可能会导致年龄的大幅低估,或者高估金属性。我们建议,在质量范围为0.25至0.85 m $ $ _ \ odot $的hyades缩放模型中,太阳能尺度进化恒星模型的未来网格可以补充。

Based on GAIA EDR3, we revisit and update our sample of bonafide single stars in the Hyades open cluster. The small observational uncertainties in parallax and photometry of EDR3 result in a tightly defined stellar sequence, which is ideal for the testing and calibration of theoretical stellar evolutionary tracks and isochrones. We benchmark the solar-scaled MESA evolutionary models against the single star sequence. We find that the non-rotating MESA models for [Fe/H] = +0.25 provide a good fit for stars with masses above 0.85, and very low mass stars below 0.25 M$_\odot$. For stars with masses between 0.25 and 0.85 M$_\odot$ the models systematically under predict the observed stellar luminosity. One potential limitation of the models for partially convective stars more massive than 0.35 M$_\odot$ is the prescription of (superadiabatic) convection with the mixing-length theory parameter $α_{\rm ML}$ tuned to match the Solar model. Below 0.35 M$_\odot$, the increased scatter in the stellar sequence might be a manifestation of the convective kissing instability, which is driven by variations in the $^3$He nuclear energy production rate due to instabilities at the convective core to envelope boundary. For a Hyades-like stellar population, the application of solar-scaled models to subsolar mass stars could result in a significant underestimate of the age, or an overestimate of the metallicity. We suggest that future grids of solar-scaled evolutionary stellar models could be complemented by Hyades-scaled models in the mass range 0.25 to 0.85 M$_\odot$.

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