基于形状的火卫一重力场研究

摘要

The methods for shape-based modeling of the gravity field of a small body are introduced.Both analytical and numerical methods are applied to the Martian moon Phobos.A 17 degree and order spherical harmonic expansion model of Phobos＇ gravity field is derived with better resolution than that of previous models.The surface gravity environment of Phobos is investigated by combining some of its dynamic parameters.Analysis results show that,due to its proximity to Mars,the tidal and centrifugal effects on Phobos can be as significant as the gravitational effect.These results will be useful for planning future missions to the Martian system,especially missions aiming at Phobos.They can also serve as references for studies of other small bodies in the solar system.%介绍基于形状对不规则小天体重力场建模的原理和方法,并通过解析法和数值法对火卫一的重力场进行正演建模。相比之前的重力场模型,基于解析算法获得的17阶次球谐展开形式重力场模型,在分辨率上有显著提高。进一步结合火卫一动力学参数,分析了火卫一表面加速度。结果显示,火卫一因其轨道十分接近火星,导致表面离心力和潮汐力十分显著,在某些区域与自引力相当,造成火卫一的特殊表面重力环境。这些结果可为未来的火卫一探测和科学研究提供基本输入物理场模型,也可为其他小天体探测中的类似问题提供方法参考。