1. 行星
a. 一个绕太阳运行的天体;
b.有足够大的质量以产生足以克服刚体应力的重力，因而 天体成流体静力学平衡状状(近球形);
c.跟邻近行星的轨道不相交;

2. 矮行星
a. 一个绕太阳运行的天体;
b.有足够大的质量以产生足以克服刚体应力的重力，因而天体成流体静力学平衡状状(近球形);
c. 与邻近天体的运行轨道相交
d. 不是卫星

3. 全职特聘
a. 一个绕地球运行的人体;
b. 有足够大的质量以产生足以克服刚体应力的重力，因而天体成流体静力学平衡状状(近"龟"形);
c. .......
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RESOLUTION 5A
The IAU therefore resolves that planets and other bodies in our Solar System be defined into three distinct categories in the following way:

(1) A planet1 is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.

(2) A dwarf planet is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape2, (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.