Description: 恒星的冕是围绕恒星大气层的极热、低密度的等离子体区域，可以在宇宙空间中延伸数百万千米。每一颗具有相当强磁场的恒星都会有一个冕，这种磁场源于恒星内部带电物质运动时产生的发电机效应。在日全食时，我们可以用肉眼观测到一个形状不规则的白色区域，环绕着被遮掩的太阳圆面，这就是太阳的冕（即“日冕”）。一般来说，恒星冕的形状是由恒星的磁场及其上部区域气体的外压决定的。恒星冕的温度非常高：例如，日冕的温度超过一百万开尔文，比太阳表面的温度高得多。将日冕加热到这一温度的机制是目前正在研究的课题，但似乎很清楚的是，贯穿日冕的磁场发挥了重要作用。日冕形状变化的时间尺度在几秒到几个月之间，主要是太阳活动所引发的，如耀斑将等离子体喷射到日冕，或日冕物质抛射释放大量带电粒子。日冕还会随着所谓的太阳周期（太阳磁场强度和方向的周期性变化，周期近 11 年）的变化而在数年的时间尺度上发生变化。预计其他恒星的冕也会发生类似的变化。

Related Terms:

• 色球
• 太阳耀斑
• 日珥
• 太阳风
• 恒星结构

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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