论文标题
从恒星科罗尼到陀螺仪学:理论和观察性探索
From Stellar Coronæ to Gyrochronology: a theoretical and observational exploration
论文作者
论文摘要
语境。恒星旋转是涉及旋转,发电机,风和磁性的复杂过程的结果。太阳能恒星的多波长调查表明,它们的旋转,X射线光度,质量损坏和磁性之间可能存在关系。这些对酷星的电晕和风施加了强烈的限制。 目标。我们的目的是提供与恒星质量损失,磁场及其基本冠状密度和温度相兼容的幂律处方,这些处方与它们的观察受到约束的旋转兼容。 方法。我们将磁场和从风扭矩公式的质量降低速率与开放簇和Skumanich定律中恒星旋转周期的分布一致。给定风模型和X射线光度从辐射损失产生的表达,我们通过假设将闭环链接到冠状孔来限制冠状特性。 结果。我们发现,磁场和质量损失涉及从旋转考虑因素约束的一对一对应关系。我们表明,磁场取决于Rossby数字和恒星质量,以保持一致的旋转模型。从我们的形式主义获得的磁场和质量损失率的估计与统计研究以及单个观察结果一致,并给出了新的引线以限制磁场旋转关系。我们得出的一组缩放法则可以广泛地应用于从PM到MS末端的酷星,并允许与迄今为止所有可用的观测约束一致的恒星风模型。
Context. Stellar spin-down is the result of a complex process involving rotation, dynamo, wind and magnetism. Multi-wavelength surveys of solar-like stars have revealed the likely existence of relationships between their rotation, X-ray luminosity, mass-losses and magnetism. Those impose strong constraints on the corona and wind of cool stars. Aims. We aim to provide power-law prescriptions of the mass-loss of stars, of their magnetic field, and of their base coronal density and temperature that are compatible with their observationally-constrained spin-down. Methods. We link the magnetic field and the mass-loss rate from a wind torque formulation in agreement with the distribution of stellar rotation periods in open clusters and the Skumanich law. Given a wind model and an expression of the X-ray luminosity from radiative losses, we constrain the coronal properties by assuming different physical scenarii linking closed loops to coronal holes. Results. We find that the magnetic field and the mass loss are involved in a one-to-one correspondence constrained from spin-down considerations. We show that a magnetic field depending on both the Rossby number and the stellar mass is required to keep a consistent spin-down model. The estimates of the magnetic field and the mass-loss rate obtained from our formalism are consistent with statistical studies as well as individual observations and give new leads to constrain the magnetic field-rotation relation. The set of scaling-laws we derived can be broadly applied to cool stars from the PMS to the end of the MS, and allow for a stellar wind modelling consistent with all the observational constraints available to date.