发表机构
The Ohio State University; Center for Cosmology and Astroparticle Physics (CCAPP)（俄亥俄州立大学; 宇宙学与高能粒子物理中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过正向建模探索古老场星的恒星减速，发现其偏离标准模型，提出质量相关项可解释该偏离，确定了可分离风驱动减速的质量相关年龄范围，倡导用正向建模开展恒星年代学研究。
AI 中文摘要
恒星年代学将恒星自转周期与年龄关联，该领域在年轻疏散星团年龄范围已得到充分研究，但古老场星区域的恒星年代学约束却很少。本研究利用自转-运动学年龄探索这一此前难以触及的星区中恒星的减速过程。采用放宽严格罗斯比标度假设的正向建模技术，我们发现恒星偏离标准减速模型的证据。这种偏离可通过恒星风全局强度中与质量相关的项，或角速度与风强度的关系来解释。带有这种额外质量相关性的模型有助于解释此前在全质量范围内拟合疏散星团自转分布的困难。此外，我们利用自转模型确定了一个与质量相关的年龄范围，在该范围内，风驱动的恒星减速可与其他物理效应分离。对于低质量恒星，该年龄范围受核心-包层耦合时标的影响最大；而高质量恒星在主序生命后期更易受惯性效应影响。使用该区域简单的解析恒星减速模型无法确定恒星风是否具有质量相关性，或恒星风是否严格为斯库马尼克（Skumanich）型。在未来自转与发电机演化研究中，我们主张采用正向建模方法开展恒星年代学研究，而非纯经验方法，因其在追踪控制恒星减速的物理效应方面更具优势。
英文摘要
Gyrochronology ties stellar rotation periods to ages. It is well studied in the young, open cluster age domain, but there are few constraints on gyrochronology in the old field star regime. In this work we use gyro-kinematic ages to explore the spin down of stars in this formerly inaccessible domain. Using forward modeling techniques which relax strict Rossby scaled assumptions, we find evidence for a departure from a standard spin down models. This departure can be explained with a mass-dependent term either in the global strength of the stellar wind or in the relationship between angular velocity and wind strength. Models with this additional mass- dependence help explain prior difficulty in fitting open cluster rotation distributions across the full mass range. Additionally, we use rotation models to identify an mass-dependent age domain over which wind driven stellar spin down can be isolated from other physical effects. For lower mass stars, this age domain is most affected by the core-envelope coupling timescale, where as higher mass stars are more subject to inertial effects late in their main sequence lifetimes. Using simple, analytic models of stellar spin down in this domain is unable to determine whether the stellar wind has a mass-dependence or if the stellar wind is strictly Skumanich-like in nature. In future studies of rotational and dynamo evolution we advocate for a forward modeling approach to gyrochronology over purely empirical approaches due to its superior ability to trace physical effects governing stellar spin down.
Comments21 Pages, 14 figures, submitted to AAS journals
