Description: 恒星的内在亮度取决于其温度和物理大小。温度越高、体积越大的恒星越亮。光谱类型是根据恒星光谱的特征进行分类。这大致反映了温度的变化。光度等级则是根据恒星与同光谱类型的其他恒星相比的亮度来分类。光度等级用罗马数字表示：主序上燃烧氢的恒星被划分为矮星（V）。例如，太阳的分类是 G2 V。在它们之上（随着大小和亮度增加）依次是亚巨星（IV）、巨星（III）、亮巨星（II）和超巨星（Ib代表亮度较低，Ia代表亮度最高）。所有这些类型的恒星都是演化了的恒星，其内核中的氢已经燃烧殆尽。贫金属亚矮星是金属含量较低的氢燃烧恒星，位于主序以下。最后，白矮星（恒星残骸）则位于主序更下方。

Related Terms:

• 矮星
• 巨星
• 赫罗图
• 光谱类型
• 超巨星
• Subdwarf Star
• 亚巨星

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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