Glossary term: 小行星
Description: 小行星是围绕太阳或其他恒星或恒星遗迹运行的小天体。小行星是由不同成分组成的固态天体：其中一些富含碳，一些含有更多岩石物质（硅酸盐），还有一些主要由金属组成。
大多数小行星都是被引力束缚在一起的碎石堆，形状凹凸不平。一些小行星拥有卫星——围绕它们运行的其他小行星。
小行星比矮行星小（矮行星的质量足以让引力把它们拉成近似圆形的形状），而比流星体大；小行星的尺寸下限通常定为1到10米之间。如果太阳或其他恒星的加热导致小天体散发出气体和尘埃，那么这个天体就是彗星而不是小行星（尽管这种区别并不总是很明显）。
在历史上，小行星这个名称用来称呼任何围绕太阳运行、但体积太小因而无法用望远镜分辨细节的天体。由于这些天体在望远镜中看起来像恒星一样，因此小行星在西方被称为“asteroids”，希腊语含义是“恒星状的天体”。
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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
The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".
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