High Ecliptic Latitude Survey for Small Main-belt Asteroids
High Ecliptic Latitude Survey for Small Main-belt Asteroids
复制标题
小型主带小行星的高黄道纬度勘测
DOI：
10.1088/0004-6256/146/5/111
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Y.
中科院分区：
文献类型：
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作者：
Terai;T.;Takahashi;J.;Itoh;Y.
主带小行星自形成以来就不断地相互碰撞。它们的大小分布主要取决于小行星强度对灾难性撞击的大小依赖。强度标度律作为物体尺寸的函数可能取决于碰撞速度，但这种关系仍然未知，特别是在相当于10 km s−1的超高速碰撞下。我们提出了在黄道纬度约为25的宽视场成像调查，以研究具有高度倾斜轨道的小型主带小行星的尺寸分布。该分析技术允许有效的小行星探测和高精度的光度测量，为估计倾角大于14的亚公里小行星的大小分布提供了足够的样本数据。累积粒径分布的最佳幂律斜率在0.6 ~ 1.0 km范围内为1.25±0.03，在1.0 ~ 3.0 km范围内为1.84±0.27。我们提供了一个简单的尺寸分布模型，该模型考虑了由于从重力尺度过渡到强度尺度而引起的幂律斜率的振荡。我们发现，与低倾角种群相比，高倾角种群的大小分布的主要成分斜率较浅。受到超高速撞击的小行星群经历了碰撞过程，与黄道小行星相比，大型天体具有更高的破坏强度和更长的寿命。
Main-belt asteroids have been continuously colliding with one another since they were formed. Their size distribution is primarily determined by the size dependence of asteroid strength against catastrophic impacts. The strength scaling law as a function of body size could depend on collision velocity, but the relationship remains unknown, especially under hypervelocity collisions comparable to 10 km s− 1. We present a wide-field imaging survey at an ecliptic latitude of about 25 for investigating the size distribution of small main-belt asteroids that have highly inclined orbits. The analysis technique allowing for efficient asteroid detections and high-accuracy photometric measurements provides sufficient sample data to estimate the size distribution of sub-kilometer asteroids with inclinations larger than 14. The best-fit power-law slopes of the cumulative size distribution are 1.25±0.03 in the diameter range of 0.6–1.0 km and 1.84±0.27 in 1.0–3.0 km. We provide a simple size distribution model that takes into consideration the oscillations of the power-law slope due to the transition from the gravity-scaled regime to the strength-scaled regime. We find that the high-inclination population has a shallow slope of the primary components of the size distribution compared to the low-inclination populations. The asteroid population exposed to hypervelocity impacts undergoes collisional processes where large bodies have a higher disruptive strength and longer lifespan relative to tiny bodies than the ecliptic asteroids.