Description: 恒星活动是用于描述磁场对恒星产生的各种影响的总称。拥有强磁场的恒星表面会出现更多星斑。恒星的磁场也可能是其日冕加热的来源，因此具有更强磁场的恒星通常会从日冕发出更多的X射线和紫外线辐射。在恒星光谱中也可以看到活动迹象，尤其是氢-α谱线的发射。这些效应综合起来可以粗略地量化恒星的“活动”程度。质量较大的恒星（光谱类型为O型、B型和早期A型）通常活动较弱。随着恒星质量的降低，活动逐渐增强，并在红矮星（M型矮星）处达到峰值。年轻恒星比老年恒星更活跃。以太阳为例，其活动遵循一个11年的周期，期间黑子的数量会发生变化。

Related Terms:

• B 型星
• 冕
• 氢
• 红矮星
• 太阳周期
• 光谱类型
• 太阳黑子
• 太阳黑子周期
• 紫外线（UV）
• M 型星
• 磁场
• O-type Star
• X射线

Term and definition status: The original definition of this term in English have been approved by a research astronomer and a teacher
The translation of this term and its definition is still awaiting approval

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