AI 中文总结
该研究通过对多个恒星形成区域年轻恒星物体的观测分析，利用多波段振幅得出斑点特性，发现快速旋转恒星小斑点覆盖常见，慢速旋转恒星小斑点寿命短，为恒星磁活动和角动量演化模型提供新证据。
AI 中文摘要
我们对通过“寻找爆发年轻恒星（HOYS）”项目观测的多个恒星形成区域中的年轻恒星物体的旋转变异性和斑点特性进行了均匀分析。从2000多个候选成员中，我们识别出144颗具有强周期信号和多波段振幅良好约束的年轻恒星物体。样本的年龄中位数约为100万年，有效温度为3500 - 6500K（质量约为0.6 - 2太阳质量），主要由2类物体组成，其中三分之一显示出内盘尘埃发射。我们从多波段振幅中得出斑点特性，发现校正观测偏差后，快速旋转恒星的固有冷斑覆盖分布可用指数函数很好地描述。这意味着小斑点覆盖在本质上比大斑点更常见。相比之下，慢速旋转恒星显示出小冷斑明显不足。考虑观测偏差和其他物理解释后，我们得出结论，慢速旋转年轻恒星物体上的小斑点寿命明显更短。这些结果为磁表面结构及其演化取决于恒星旋转提供了新证据，对年轻恒星的磁活动和角动量演化模型提出了新的经验约束。
英文摘要
We present a homogeneous analysis of rotational variability and spot properties in young stellar objects across multiple star-forming regions observed by the Hunting Outbursting Young Stars (HOYS) project. From over 2000 candidate members, we identify 144 YSOs with robust periodic signals and well-constrained multi-band amplitudes. The sample has a median age of $\sim$1~Myr, effective temperatures of 3500--6500~K (masses $\sim$0.6--2~M$_\odot$), and is dominated by Class~2 objects, one third of which exhibit inner disc dust emission. The rotation period distribution is strongly bimodal, with 55 percent fast rotators ($P<5.5$~d) and 45 percent slow rotators. Fast rotators are predominantly inner disc-less, whereas slow rotators include both disc-bearing and disc-free systems, indicating that disc braking alone cannot explain the observed rotational states. We derive spot properties from multi-band amplitudes and find that, after correcting for observational biases, the intrinsic cold-spot coverage distribution of fast rotators is well described by an exponential function. This implies that small spot coverages are intrinsically much more common than large ones, consistent with stochastic magnetic flux emergence governing spot formation. In contrast, slow rotators show a pronounced deficit of small cold spots. After considering observational biases and alternative physical explanations, we conclude that small spots on slowly rotating YSOs have significantly shorter lifetimes. These results provide new evidence that magnetic surface structure and its evolution depend on stellar rotation, placing new empirical constraints on models of magnetic activity and angular momentum evolution in young stars.
CommentsAccepted for publication by MNRAS, 9 figures, 3 tables
