标题： 近地小行星的近日点最小距离及相关的停留时间 显示英文标题

标题： Minimum perihelion distances and associated dwell times for near-Earth asteroids

摘要： 观测到的近地小行星种群中，具有小近日点距离（例如，q<=0.2 天文单位）的小行星非常少。目前轨道近日点距离较大的NEAs可能在过去经历过一段更接近太阳的演化过程。我们提出了对小行星在其轨道历史中达到的最小近日点距离的概率评估。同时，我们提供了停留时间的估计，即近日点距离处于特定范围内的持续时间。我们重新分析了测试小行星从进入近地区域开始的轨道积分，直到它们与主要天体相撞或被抛出内太阳系。我们考虑了在特定近日点距离下小行星的总破坏作为绝对星等（H）的函数。我们计算了具有给定轨道要素和H的小行星达到小于给定阈值的近日点距离及其在该范围内的停留时间的概率。我们构建了一个查找表，可用于研究小行星的过去轨道和热演化以及陨石坠落及其可能的母体。对25次陨石坠落的应用表明，碳质球粒陨石通常在小近日点距离下有较短的停留时间，而普通球粒陨石的停留时间则在10,000至500,000年之间。缺乏长时间停留且最小近日点距离较小的陨石坠落支持了在小近日点距离下小行星的超级灾难性破坏。 显示英文摘要

摘要： The observed near-Earth asteroid population contains very few objects with small perihelion distances, say, q<=0.2 au. NEAs that currently have orbits with larger q might be hiding a past evolution during which they have approached closer to the Sun. We present a probabilistic assessment of the minimum q that an asteroid has reached during its orbital history. At the same time, we offer an estimate of the dwell time, that is, the time q has been in a specific range. We have re-analyzed orbital integrations of test asteroids from the moment they enter the near-Earth region until they either collide with a major body or are thrown out from the inner Solar System. We considered a total disruption of asteroids at certain q as a function of absolute magnitude (H). We calculated the probability that an asteroid with given orbital elements and H has reached a q smaller than a given threshold value and its respective dwell time in that range. We have constructed a look-up table that can be used to study the past orbital and thermal evolution of asteroids as well as meteorite falls and their possible parent bodies. An application to 25 meteorite falls shows that carbonaceous chondrites typically have short dwell times at small q, whereas for ordinary chondrites it ranges from 10,000 to 500,000 years. A dearth of meteorite falls with long dwell times and small minimum q supports a super-catastrophic disruption of asteroids at small q.