The operational environment and rotational acceleration of asteroid (101955) Bennu from OSIRIS-REx observations
The operational environment and rotational acceleration of asteroid (101955) Bennu from OSIRIS-REx observations
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DOI：
10.1038/s41467-019-09213-x
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发表时间：
2019-03-19
影响因子：
16.6
通讯作者：
Marty, B.
中科院分区：
文献类型：
--
作者：
Hergenrother, C. W.;Maleszewski, C. K.;Marty, B.
在接近小行星(101955)本努的过程中，美国国家航空航天局的起源、光谱解释、资源识别和安全-巨龙探测器(OSIRIS-Rex)航天器调查了本努的直接环境、光度特性和自转状态。如果发现尘土飞扬的环境、天然卫星或意想不到的小行星特征，都会对飞行任务的安全和观测战略产生影响。在这里，我们显示航天器在这一时期的观测对卫星高度敏感(亚米级)，但没有发现，尽管后来的导航图像表明需要进一步的调查。我们将2018年9月本努地表的平均扬尘产量限制在150g的上限，S(-1)平均超过34分钟。Bennu的圆盘积分光度相函数验证了相遇前天文运动的测量结果。我们证明了Bennu的自转速度每天(-2)以3.63+/-0.52x10(-6)度持续加速，这可能是由于Yarkovsky-O‘Keefe-Radzievskii-Paddack(YORP)效应，具有演化意义。
During its approach to asteroid (101955) Bennu, NASA's Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) spacecraft surveyed Bennu's immediate environment, photometric properties, and rotation state. Discovery of a dusty environment, a natural satellite, or unexpected asteroid characteristics would have had consequences for the mission's safety and observation strategy. Here we show that spacecraft observations during this period were highly sensitive to satellites (sub-meter scale) but reveal none, although later navigational images indicate that further investigation is needed. We constrain average dust production in September 2018 from Bennu's surface to an upper limit of 150 g s(-1) averaged over 34 min. Bennu's disk-integrated photometric phase function validates measurements from the pre-encounter astronomical campaign. We demonstrate that Bennu's rotation rate is accelerating continuously at 3.63 +/- 0.52 x 10(-6) degrees day(-2), likely due to the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect, with evolutionary implications.