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NEO Population, Velocity Bias, and Impact Risk from an ATLAS Analysis
The Planetary Science Journal ( IF 3.8 ) Pub Date : 2021-01-28 , DOI: 10.3847/psj/abd325
A. N. Heinze 1 , Larry Denneau 1 , John L. Tonry 1 , Steven J. Smartt 2 , Nicolas Erasmus 3 , Alan Fitzsimmons 2 , James E. Robinson 2 , Henry Weiland 1 , Heather Flewelling 1 , Brian Stalder 4 , Armin Rest 5, 6 , David R. Young 2
Affiliation  

We estimate the total population of near-Earth objects (NEOs) in the solar system using an extensive, “solar-system-to-pixels” fake-asteroid simulation to debias detections of real NEOs by the ATLAS survey. Down to absolute magnitudes H = 25 and 27.6 (diameters of ∼34 and 10 m, respectively, for 15% albedo), we find total populations of (3.72 0.49) 105 and (1.59 0.45) 107 NEOs, respectively. Most of the plausible sources of error tend toward underestimation, so the true populations are likely larger. We find the distribution of H magnitudes steepens for NEOs fainter than H ∼ 22.5, making small asteroids more common than extrapolation from brighter H mags would predict. Our simulation indicates a strong bias against detecting small but dangerous asteroids that encounter Earth with high relative velocities—i.e., asteroids in highly inclined and/or eccentric orbits. Worldwide NEO discovery statistics indicate this bias affects global NEO detection capability to the point that an observational census of small asteroids in such orbits is probably not currently feasible. Prompt and aggressive followup of NEO candidates, combined with closer collaborations between segments of the global NEO community, can increase detection rates for these dangerous objects.



中文翻译:

来自ATLAS分析的NEO人口,速度偏差和影响风险

我们使用广泛的“太阳系到像素”假小行星模拟来估计太阳系中近地天体(NEO)的总数,以通过ATLAS勘测对真实NEO的探测进行反偏。下降到绝对值H = 25和27.6(对于15%的反照率,直径分别为〜34和10 m),我们发现总人口分别为(3.72 0.49)10 5和(1.59 0.45)10 7 NEO。大多数可能的错误来源都倾向于低估,因此真实的种群可能更大。我们发现的分布^ h幅度变陡的近地天体的微弱比^ h〜22.5,使小行星共同比外推亮^ hmags会预测。我们的模拟表明强烈反对检测以相对高速度遇到地球的小型但危险的小行星,即,处于高度倾斜和/或偏心轨道的小行星。全球近地天体的发现统计数据表明,这种偏见影响了全球近地天体的探测能力,以至于目前尚无法对这种轨道上的小行星进行观测普查。对NEO候选人进行及时而积极的跟踪,再加上全球NEO社区各部门之间的紧密合作,可以提高对这些危险物体的发现率。

更新日期:2021-01-28
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