A Monte Carlo Method for Evaluating Empirical Gyrochronology Models and Its Application to Wide Binary Benchmarks
A Monte Carlo Method for Evaluating Empirical Gyrochronology Models and Its Application to Wide Binary Benchmarks
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DOI：
10.3847/1538-4357/ac6035
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发表时间：
2021-05
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通讯作者：
T. Otani;T. Hippel;D. Buzasi;T. Oswalt;Alexander Stone-Martinez;Patrice Majewski Embry-Riddle Aeronautical University-Patrice-Majewski-Embry-Riddl
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作者：
T. Otani;T. Hippel;D. Buzasi;T. Oswalt;Alexander Stone-Martinez;Patrice Majewski Embry-Riddle Aeronautical University-Patrice-Majewski-Embry-Riddl
准确的恒星年龄对于我们理解银河系星星的形成历史和化学演化以及约束系外行星形成模型至关重要。陀螺年代学是恒星自转和年龄之间的关系，它似乎可以提供一个可靠的年龄指标，用来指示质量范围在0.6-1.3 M <$.的主序星。这些恒星由于磁制动而失去角动量，因此它们的旋转速度随着年龄的增长而下降。虽然目前的陀螺年代学关系已经相当好地测试了年轻的MS星与质量大于1 M <$，主要是在年轻的疏散星团，不足的测试存在较老和较低质量的MS星。双星提供了扩大和填补年龄和金属丰度范围的潜力，在这些范围内，陀螺年代学可以进行经验检验。在本文中，我们展示了一个Monte Carlo方法来评估gyrochronology模型使用双星。作为例子，我们使用了五个以前发表的宽二进制对。我们还展示了一个蒙特卡罗方法来评估来自每个gyrochronology模型的年龄的精度和准确性。对于传统的Skumanich模型，对于B − V = 0.65的恒星，其年龄不确定度为σ age/age = 15%~ 20%，对于自转周期P ≤ 20天、B − V = 1.5的恒星，其年龄不确定度为σ age/age = 5%~ 10%.
Accurate stellar ages are essential for our understanding of the star formation history of the Milky Way and Galactic chemical evolution, as well as to constrain exoplanet formation models. Gyrochronology, a relationship between stellar rotation and age, appears to offer a reliable age indicator for main-sequence (MS) stars over the mass range of approximately 0.6–1.3 M ⊙. Those stars lose their angular momentum due to magnetic braking and as a result their rotation speeds decrease with age. Although current gyrochronology relations have been fairly well tested for young MS stars with masses greater than 1 M ⊙, primarily in young open clusters, insufficient tests exist for older and lower mass MS stars. Binary stars offer the potential to expand and fill in the range of ages and metallicity over which gyrochronology can be empirically tested. In this paper, we demonstrate a Monte Carlo approach to evaluate gyrochronology models using binary stars. As examples, we used five previously published wide binary pairs. We also demonstrate a Monte Carlo approach to assess the precision and accuracy of ages derived from each gyrochronology model. For the traditional Skumanich models, the age uncertainties are σ age/age = 15%–20% for stars with B − V = 0.65 and σ age/age = 5%–10% for stars with B − V = 1.5 and rotation period P ≤ 20 days.