Giga-year dynamical evolution of particles around Mars
Giga-year dynamical evolution of particles around Mars
复制标题
火星周围粒子的千兆年动力学演化
DOI：
10.1016/j.icarus.2022.115335
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发表时间：
2023
期刊：
影响因子：
3.2
通讯作者：
Hyodo Ryuki
中科院分区：
文献类型：
--
作者：
Liang Yuying;Hyodo Ryuki
火星周围可能存在各种大小的粒子。大粒子的轨道主要由火星引力控制，而小粒子的轨道则可能受到非引力的显著影响。在过去的2001 - 2004年里，许多关于火星周围粒子动力学的研究都集中在相对较小的粒子（半径为rp ≤ 100 μ m）上。本文采用直接数值轨道积分和解析方法，考虑火星引力、J2、太阳辐射压（SRP）和Poynting-Robertson（PR）力，研究了火星赤道面附近轨道半径从微米到米的粒子的十亿年动力学演化。我们还新研究了行星阴影对粒子动力学的影响。我们的研究结果表明，小粒子（rp <$10 μ m）最初在0.88火星半径（低于今天的火卫二轨道）被快速移动的SRP由于偏心率增加，导致与火星碰撞的近心距离。较大粒子（rp> 10 μ m）的轨道由于PR力而缓慢衰减（时间尺度> 104年）。行星阴影减少了轨道上的阳光照射面积，从而降低了PR阻力的效率。然而，我们表明，即使包括行星阴影，粒子半径达100厘米，最初在108火星半径，最终螺旋到火星表面在109年。较小的粒子到达火星所需的时间较短，反之亦然。我们的研究结果将是重要的，以更好地理解和约束火星周围的剩余粒子的性质在火卫一和火卫二形成的巨大影响假说的背景下。
Particles of various sizes can exist around Mars. The orbits of large particles are mainly governed by Martian gravity, while those of small particles could be significantly affected by non-gravitational forces. Many of the previous studies of particle dynamics around Mars have focused on relatively small particles (radius of r p≲ 100 μ m) for≲ 1 0 4 years. In this paper, using direct numerical orbital integration and analytical approaches, we consider Martian gravity, Martian J 2, the solar radiation pressure (SRP) and the Poynting–Robertson (PR) force to study the giga-year dynamical evolution of particles orbiting near the Martian equatorial plane with radius ranging from micrometer to meter. We also newly study the effect of the planetary shadow upon the particle dynamics. Our results show that small particles (r p≲ 10 μ m) initially at≲ 8 Martian radii (below the orbit of today’s Deimos) are quickly removed by the SRP due to eccentricity increase, resulting in a collision with Mars at the pericenter distance. The orbits of larger particles (r p> 10 μ m) slowly decay due to the PR forces (timescale of> 1 0 4 years). The planetary shadow reduces the sunlit area in the orbit and thus the efficiency of the PR drag force is reduced. However, we show that, even including the planetary shadow, particles up to∼ 10 cm in radius, initially at≲ 8 Martian radii, eventually spiral onto the Martian surface within∼ 1 0 9 years. Smaller particles require less time to reach Mars, and vice versa. Our results would be important to better understand and constrain the nature of the remaining particle around Mars in a context of giant impact hypothesis for the formation of Phobos and Deimos.