Description: 褐矮星是一种既非恒星也非行星的天体，它的质量相较于恒星来说太小，但相较于行星来说又太大。恒星的能量来源是核心中的氢聚变。褐矮星的内部温度太低，无法维持氢聚变。不过，褐矮星在其生命早期能够短暂地进行氘聚变，氘是氢的一种较重形式。这种氘聚变被用来区分褐矮星和行星，但很难观测到。褐矮星的质量通常在太阳质量的1.2%到8%之间（大约是木星质量的12到80倍），尺寸与木星大致相同。年轻褐矮星外部区域的温度（有效温度）与小质量恒星（红矮星）相近，但由于缺乏内部热源，它们会随着年龄的增长而冷却，有些会冷却到几百摄氏度。

Related Terms:

• 氢
• 氢聚变
• 木星
• 质量
• 行星
• 红矮星
• 有效温度
• 恒星活动

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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