恒星形成区的年龄分布？
Age spreads in star forming regions?
摘要：
在恒星形成区内，主序前恒星的自转周期和投影赤道速度可以结合起来，得到投影恒星半径。假设随机的轴向取向，蒙特卡洛模型被用来说明，投影恒星半径的分布是非常敏感的年龄和年龄分散之间的1和10百万年，这与传统的赫兹斯普朗-罗素图的年龄估计，是相对免疫的不确定性，由于灭绝，变异，应用该技术的猎户座星云团揭示了一个因素的2- 3（FWHM）在一个给定的有效温度的半径扩展。将这种分散模拟为年龄分布表明，ONC中的PMS恒星的年龄范围大于平均星团年龄，这可以通过从赫兹斯普朗-罗素图推导出的年龄分布来合理地描述。当考虑PMS性质（旋转，圆盘等）的演化时，这些半径/年龄的差异肯定足够大，足以使共演化的假设失效。从一个年轻的星团到另一个
英文摘要：
Rotation periods and projected equatorial velocities of pre-main-sequence (PMS) stars in star forming regions can be combined to give projected stellar radii. Assuming random axial orientation, a Monte-Carlo model is used to illustrate that distributions of projected stellar radii are very sensitive to ages and age dispersions between 1 and 10 Myr which, unlike age estimates from conventional Hertzsprung-Russell diagrams, are relatively immune to uncertainties due to extinction, variability, distance etc. Application of the technique to the Orion Nebula cluster reveals radius spreads of a factor of 2--3 (FWHM) at a given effective temperature. Modelling this dispersion as an age spread suggests that PMS stars in the ONC have an age range larger than the mean cluster age, that could be reasonably described by the age distribution deduced from the Hertzsprung-Russell diagram. These radius/age spreads are certainly large enough to invalidate the assumption of coevality when considering the evolution of PMS properties (rotation, disks etc.) from one young cluster to another.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
